Image recording body and image forming apparatus by use of the same

ABSTRACT

There is provided improvement of a light-heat conversion in a light-stimulated writing method.  
     An image recording body includes an element, which absorbs light (electromagnetic wave), provided in a surface of a recording body  10 , or in a recording layer formed on uppermost layer of the recording body having a material exhibiting thermal changeable character of wettabilty, or in a substrate or an intermediate layer of the recording body. After a liquid is on the recording body  10  by a liquid forming means  3 , light-stimulated writing is carried out. When the light-stimulated writing is carried out with light (electromagnetic wave) from a light (electromagnetic wave) source according to image information, an efficiency of light-heat conversion can be enhanced by a light (electromagnetic wave)—absorbing element.

TECHNICAL FIELD

The present invention relates generally to an image recording body andan image forming apparatus by use of the image recording body, and moreparticularly to a structure of the image recording body in order to forma latent image by means of a light (or heat)-stimulated writing method,improvement of a light-to-heat conversion efficiency during alight-stimulated writing operation, a long-life operation of a sourcefor writing, an adjustment of a light (or heat) amount during thelight-stimulated writing operation, a method for removing an inkremaining on the image recording body and a method for forming thelatent image thereon.

BACKGROUND ART

FIG. 1 illustrates a schematic view of an essential part of an imageforming apparatus of an embodiment according to the present invention.As shown in FIG. 1, the image forming apparatus comprises a heatingsource 1, a recording roller 2, an inking unit 3, an intermediatetransfer roller 4, a recording paper 5, a pressure roller 6, an infraredheater 7, a cleaning unit 8, a liquid layer-forming roller 9 and animage recording body 10. Examples of the heating source 1 (preferablylight source having a wavelength from 300 nm to 1300 nm) include alight-emitting diode array (which is hereinafter referred to as LEDarray), a semiconductor laser, a solid laser or the like. The imagerecording body 10 has surface characteristics that a receding contactangle decreases when a surface of the image recording body in a heatedstate is brought into contact with a liquid (hereinafter referred to asa liquid-attracting state), and the receding contact angle increaseswhen the image recording body is heated in a state where the imagerecording body is not contact with the liquid (hereinafter referred toas a liquid-repelling state).

When the surface of the image recording body 10 is treated to become theliquid-attracting state, a liquid layer is formed on the surface of theimage recording body 10 before the surface of the image recording body10 is heated, or a liquid is come into contact with the surface of theimage recording body 10 during a heating operation, or the liquid iscome into contact with the surface of the image recording body 10 rightafter the surface is heated. As shown in FIG. 1, it is possible to formthe liquid layer on the image recording body 10 by means of the liquidlayer-forming roller 9. However, it is not necessary to use the liquidlayer-forming roller 9 for formation of the liquid layer. For example,it is possible for the image recording body 10 to remove from therecording roller 2 or for the recording roller 2 to dip in the liquid,or for the liquid layer to form on the surface of the image recordingbody 10 by means of the cleaning unit 8.

As mentioned above, after the surface of the recording body becomes theliquid-attracting state, writing of an image can be carried out thereon.This image writing can be performed by scanning the heating source 1with separation of the image recording body 10 from the inking unit 3,the intermediate transfer roller 4, the cleaning unit 8 or the like. Asa scanning method, writing can be carried out by moving the heatingsource 1 in a main scanning direction by a linear motor or the likewhile rotating the recording roller 2, or a raster scanning can beapplied for writing by means of polygon mirror or galvano mirror.

The image is then formed on the image recording body 10 and at thisimage forming period the recording paper 5 is fed while pressing theimage recording body 10 with the intermediate transfer roller 4 and theinking unit 3. As the inking unit 3, a plurality of inking rollers canbe used in order to control a thickness of an ink layer by means of ablade or the like 3 b. An ink can be supplied from an upper portion ofthe blade 3 b by dropping an ink from an ink supply container 3 a.

After printing a desired press run, it is possible to reuse the imagerecording body 10 by forming another image thereon newly. At this time,that is to say, at the end of printing, the intermediate transfer roller4 and the inking roller 3 are separated from the image recording body 10and the cleaning unit 8 is brought into contact with the image recordingbody 10 so that the ink remaining thereon can be removed. After removalof the ink remaining on the image recording body 10, another liquidlayer is formed on the surface of the image recording body 10 and theimage recording body 10 is heated by means of the infrared heater 7 totreat the surface of the image recording body 10 so as to become theliquid-attracting state, while erasing the latent image of the previousimage. However, in addition to the above method, as a method for treatthe surface of the image recording body 10 so as to become theliquid-attracting state, it is possible to heat in a state where theliquid is come into contact with the surface of the image recording body10 or for the surface of the image recording body 10 to bring intocontact with the liquid right after heating the surface. In other words,as mentioned above, after printing a predetermined press run on therecording paper 5, the ink remaining on the image recording body 10 isremoved and the latent image (a liquid-repelling region) formed on theimage recording body 10 is erased, and the surface of the imagerecording body is then treated so as to become the liquid-attractingstate. In this way, a new image (a latent image) can be formed on theimage recording body 10 so that the image recording body 10 can bereused. That is to say, reuse of the image recording body 10 can beachieved by the following steps of: removing the ink remaining on theimage recording body 10; forming the liquid layer on the surface of theimage recording body by means of the liquid layer-forming roller 9; andheating the surface of the image recording body 10 by means of theinfrared heater 7 to perform the liquid attracting treatment of theimage recording body 10. As the cleaning unit 8, it is possible to use awaste 8 b soaked with a cleaning liquid from the cleaning supplycontainer 8 a. The surface of the image recording body 10 is washed bypressing it with this waste 8 b.

In writing of the image into the image recording body, there arepositive writing and negative writing. As negative writing, by heatingthe image recording body 10 in a state where the body 10 is come intocontact with an element selected from the liquid and/or a solid, orbrought into contact with the element selected from the liquid and/orthe solid right after the surface of the image recording body 10 isheated, the receding contact angle of an image region of the imagerecording body decreases so as to subject the surface of the imagerecording body 10 to the liquid-attracting treatment. By selectivelyheating a non-image region of the image recording body in the absence ofthe above contacting element, the receding contact angle of thenon-image region of the image recording body increases so as to subjectthe surface of the image recording body to the liquid-repellingtreatment. On the other hand, as positive writing, by selectivelyheating only the image region of the image recording body 10 in a statewhere the body is come into contact with the element selected from theliquid and/or the solid, or selectively brought into contact with theelement selected from the liquid and/or the solid right afterselectively heating the surface of the body, the image region of theimage recording body 10 is subjected to the liquid-attracting treatment.

As stated above, in the image forming apparatus according to the presentinvention, the liquid-attracting treatment is performed on the imagerecording body 10 according to image information. The ink is attached toportions of the image recording body 10 subjected to theliquid-attracting treatment and the ink attached to the body 10 can bedirectly transferred to the recording paper 5 through the intermediatetransfer roller 4 so as to achieve transfer and printing steps.

As described above, the image recording body 10 can be reused by thefollowing steps of: printing the predetermined press run onto therecording paper 5; erasing the latent image (the liquid-attractingregion) formed on the body 10 and removing the ink-remaining thereon;and forming a new image (the latent image) on the body 10. That is tosay, reuse of the image recording body 10 can be carried out by removingthe ink remaining on the body 10 by use of the cleaning unit 8 or othermeans and then heating the image recording body 10 by means of theinfrared heater 7 to provide the liquid-attracting state for the surfaceof the image recording body 10.

Japanese Laid-Open Patent Application No. 3 describes a recording methodby use of a thermosensitive material having changeable character ofwettability. Japanese Laid-Open Patent Application No. 8-276663describes a recording method by negative writing. However, the inventionof the above patent application No. 3-178478 mainly relates to therecording method by means of a thermal head in which there may beoccasions that a recording layer is mechanically damaged due to contactrecording between the thermal head and a recording body having therecording layer. Also, for the recording method by negative writingdescribed in the above patent application No. 0.8-276663, an efficiencyof light-heat conversion of a light source is not enough high because ofcontinuous oscillation of the light source. There are problems thatwriting for the above method is time-consuming and is required to employan expensive device as the light source.

Further, in the recording method disclosed in the above patentapplication No. 8-276663, there are disadvantages that a lifetime of thelight source is shorter as compared to positive writing.

Moreover, in a case where the above recording body having a light-heatconverting layer, for example in a case of writing by means of laserlight, when incident light from a surface of the recording layer isreflected at a surface of a substrate through the recording layer andthe light-heat converting layer, regular reflecting component is strongand this component reaches a boundary surface between the light-heatconverting layer and the recording layer or the surface of the recordinglayer, thereby leading to multi-reflections within the above layers.This results in spreading of exposed areas and a recording irregularity,such as a more.

In addition, in order to reuse the recording body used once, a clearprinting can not be performed with a recording paper fouled by theremaining ink unless the ink remaining on the recording body is removedcompletely.

Furthermore, in a case of writing to the recording body by use of aplurality of heating means, if only one of the heating means is broken,a non-image region which is not heated is produced, thereby giving riseto a line of scumming.

In a case where negative writing is also carried out, an irregularity inheating and cumulative heat of an image forming means during negativewriting operation cause the image to be degraded.

In a case where negative writing is also performed through a rotatingmulti-face mirror, if sensitivity of the recording body is low, arotation rate of the rotating multi-face mirror must be low, so that therotation rate is unstable because of the absence of an action of inertiainduced by the rotation. This result in an irregularity of thelight-heat conversion, thus producing irregularities relating to animage density, dot size and dot line.

DISCLOSURE OF INVENTION

A technical feature of the present invention resides in an imagerecording body comprising an element, which absorbs light (whichincludes an electromagnetic wave) in response to image information toachieve recording, provided in a recording layer of the image recordingbody formed on an uppermost layer thereof comprising a material havingthermal changeable character of wettability, or in a substrate of saidimage recording body or an intermediate layer thereof, thereby improvinga light-heat conversion efficiency in the light-stimulated writing.

The present invention provides the recording body having the highestefficiency of the light-heat conversion, in which the material havingthe thermal changeable character of wettability includes an organicmaterial comprising an element having the changeable character ofwettability and an element which absorbs the light (which includes theelectromagnetic wave) in response to image information to achieverecording.

According to the above invention, by dissolving or dispersing a dye or apigment which absorb light (which includes the electromagnetic wave) inthe material which exhibits the thermal changeable character ofwettability so as to contain the dye or the pigment in the abovematerial, the recording body comprises a recording material and aabsorbing material, so that there is a wider selection for the recordingand the absorbing materials.

According to the above invention by providing a reflecting layer whichreflects light (which includes the electromagnetic wave) placed betweenthe recording layer comprising the material having the changeablecharacter of wettability and the substrate, a number of reflectionstakes place at the recording body so that a optical path length in therecording layer extends, thereby increasing the efficiency of thelight-heat conversion.

According to the above invention, a rough surface of the reflectinglayer results in a scattering of the light, so that an even penetrationof the light can be carried out.

The present invention further provides a recording apparatus by use ofthe recording body comprising the material showing the changeablecharacter of wettability which is sensitive of heat, in which scannablelight can be used as an image writing source and a long lifetime of thewriting source can be realized as a positive light-stimulated writing byproviding a liquid layer forming means for forming a liquid layer on asurface irradiated by the light of the recording body during thelight-stimulated writing.

According to the above invention, when the liquid layer forming means ismeans for forming a gel-like element, both of an easy holding of theliquids layer and a liquid supply can be realized simultaneously,According to the above invention, when the liquid layer forming means ismeans for forming a layer comprising a microcapsule-like fine particleelement containing a liquid, stability both for the liquid supply andthe liquid storage can be ensured.

According to the above invention, by providing a light (which includesthe electromagnetic wave) transmissible film for the liquid layerforming means in order to keep the liquid layer between the liquidforming means and the surface of the recording body so as to form thefilm on the surface of the recording body in a state where the liquid isplaced between the liquid layer forming means and the recording body, aHigh speed writing can by obtained easily.

The recording body according to the present invention comprises arecording layer, a light-heat converting layer, a base body and aregular reflection-preventing layer between the base body and thelight-heat converting layer to inhibit the regular reflection of lightwhich is used for writing. This results in weakness of the regularreflection component in a case of reflection at a surface of the basebody, so that multi-reflection can be lowered within each layer.

The recording body according to the present invention comprises therecording layer, the light-heat converting layer, the base body has afinely irregular structure provided on a surface of a light-heatconverting layer side thereof in order to inhibit the regular reflectionof light which is used for writing. This results in weakness of theregular reflection component of the light without an increase in thenumber of the layer, so that multi-reflection can be lowered within eachlayer.

The recording body according to the present invention comprises arecording layer having a light-heat converting agent dispersed therein,a regular reflection-preventing layer to inhibit the regular reflectionof light which is used for writing and passes through the recordinglayer and a base body carrying the regular reflection-preventing layer.The regular reflection component is weakened in a case of reflection ata surface of the base body, thereby lessening multi-reflection withineach layer.

The recording body according to the present invention comprises arecording layer having a light-heat converting agent dispersed thereinand a base body carrying the recording layer. By providing an finelyirregular structure on a surface of a recording layer side of the basebody in order to inhibit the regular reflection of light which is usedas writing and passes through the recording layer, the regularreflection component can be weakened in the event of reflection at thebase body of the substrate without increase in the number of the layer,so that multi-reflection can be lowered within each layer.

Since the recording body according to the present invention comprises arecording layer, a light-heat converting layer, a transparent base bodyand a regular reflection-preventing layer to inhibit the regularreflection of light which is used to record onto an opposite side of thelight-heat converting layer to the transparent base body, a regularreflection component can be weakened in a case of reflection at a backsurface of the transparent base body, so that multi-reflection can belowered within each layer.

The recording body according the present invention comprises a recordinglayer, a light-heat converting layer and a transparent base body. Sincethe transparent base body comprises a back surface thereof having afinely irregular structure, the surface being arranged in an oppositeside to the light-converting layer having the finely irregularstructure, the regular reflection component can be weakened in the eventof the reflection at the back surface of the transparent base bodywithout increase in the number of the layer.

Since the recording body according to the present invention comprises arecording layer having a light-heat converting agent dispersed therein,a transparent base body carrying the recording layer, a regularreflection-preventing layer provided on a surface arranged in anopposite side to the recording layer on the transparent base body inorder to inhibit the regular reflection of light which is used forrecording, the regular reflection component can be weakened in a case ofreflection at a back surface of the transparent base body, so thatmulti-reflection can be lowered within each layer.

Since the recording body according to the present invention comprises arecording layer having a light-heat converting agent dispersed thereinand a transparent base body, the transparent base body having a finelyirregular structure on an opposite surface to the light-heat convertinglayer, the regular reflection component can be weakened in the event ofreflection at the back surface of the transparent base body withoutincrease in the number of the layer, so that multi-reflection can belowered within each layer.

According to the present invention, in a carrier of the recording bodycarrying a transparent recording medium against light which is used forrecording, by providing a reflecting layer on the surface of the carrierof the recording body in order to inhibit the regular reflection of thelight which is used for recording, the regular reflection component canbe weakened in the event of the reflection at the surface of thecarrier, so that multi-reflection can be lowered within each layer.

According to the present invention, in a carrier of the recording bodycarrying a transparent recording medium against the light which is usedfor recording, by providing a finely irregular structure on the surfaceof the carrier, the regular reflection component can be weakened in acase of reflection at the surface of the carrier without increase in thenumber of the layer, so that multi-reflection can be lowered within eachlayer.

The recording body according to the present invention comprises arecording layer having the thermal changeable character of wettabilityand a substrate carrying the recording layer. The recording layer of therecording body is heated to form a latent image on the recording layerand the latent image is developed to transfer to a recording paper. Therecording body has a surface having a roughness of less than 20 μm.

The recording body according to the present invention comprises arecording layer having the thermal changeable character of wettabilityand a substrate carrying the recording layer. The recording layer of therecording body is heated to form the latent image on the recording layerand the latent image is then developed to transfer to the recordingpaper. The recording body has the recording layer having a pencilhardness of more than H.

The recording body according to the present invention comprises arecording layer having the thermal changeable character of wettabilityand a substrate carrying the recording layer. The recording layer of therecording body is heated to form the latent image on the recording layerand the latent image is developed to transfer to the recording paper.The recording body has the recording layer having a Young's modulus ofless than 1.0×10⁷ N/m² and a thickness of more than 2 μm.

The recording body according to the present invention comprises arecording layer having the thermal changeable character of wettabilityand a substrate carrying the recording layer. The recording layer of therecording body is heated to form the latent image on the recording layerand the latent image is then developed to transfer to the recordingpaper. The recording body has the substrate having a Young's modulus ofless than 5.0×10⁸ N/m² and a thickness of more than 25 μm.

The recording body according to the present invention comprises arecording layer having the thermal changeable character of wettability,a substrate and a cushion layer which is placed between the recordinglayer and the substrate and has a elastic property. The recording layerof the recording body is heated to form the latent image on therecording layer and the latent image is then developed to transfer tothe recording paper. The recording body comprises the cushion layerhaving a Young's modulus of less than 8.0×10⁷ N/m² and a thickness ofmore than 5 μm.

According to the present invention, a method of removing an inkremaining on a recording body having the thermal changeable character ofwettability, the method comprising the steps of coating a liquid whichis compatible with a resin and a pigment which are contained in arecording ink on the recording body, and then wiping the liquid thuscoated.

According to the present invention, a method of removing an inkremaining on a recording body having the thermal changeable character ofwettability, the method comprising the steps of coating aninvolatilizable or a volatilizable solvent which is contained in arecording ink on the recording body, and then wiping the solvent thuscoated.

According to the present invention, a method of removing an inkremaining on a recording body having the thermal changeable character ofwettability, the method comprising the steps of coating a liquid whichis compatible with a resin and a pigment which are contained in arecording ink on the recording body, and then supersonically cleaningthe recording body.

According to the present invention, a method of removing an inkremaining on a recording body having the thermal changeable character ofwettability, the method comprising the steps of coating ainvolatilizable or a volatilizable solvent which is contained in arecording ink on the recording body, and then supersonically cleaningthe recording body.

According to the present invention, the surface of the recording body iscleaned after removal of the ink remaining on the recording body by anyone of the methods described above.

According to the present invention, a method of removing an inkremaining on a surface of a recording body having the changeablecharacter of wettability, the method comprising the steps of bringing aadhesive element into contact with the surface of the recording bodydeveloped already, and then stripping the adhesive element from thesurface of the recording body, so that the remaining ink can be removedfrom the surface of the recording body together with the adhesiveelement.

According to the present invention, a method of removing an inkremaining on a surface of a recording body having the changeablecharacter of wettability, the method comprising the steps of bringing anelement having a rougher surface than that the surface of the recordingbody into contact with the surface of the recording body developedalready, and then stripping the element from the surface of therecording body, so that the remaining ink can be removed from thesurface of the recording body together with the element.

According to the present invention, a method of removing an inkremaining on a surface of a recording body having the changeablecharacter of wettability, the method comprising the steps of forming asolid film on the surface of the recording body developed already, andthen stripping the solid film from the surface of the recording body, sothat the remaining ink can be removed from the surface of the recordingbody together with the solid film.

According to the present invention, a method of removing an inkremaining on a surface of a recording body having the changeablecharacter of wettability, the method comprising the steps of completelycuring the ink remaining on the surface of the recording body by an airdrying, and then removing the ink by any one of the method describedabove.

According to the present invention, a method of removing an inkremaining on a surface of a recording body having the changeablecharacter of wettability, the method comprising the steps of completelycuring the ink remaining on the surface of the recording bodycompulsorily, and then removing the ink by any one of the methoddescribed above.

According to the present invention, an image forming apparatuscomprising an image forming means for forming a latent image on an imageregion of a recording body by selectively heating a non-image region ofa recording body, in which the latent image formed on the recording bodyis developed to transfer to a recording paper, wherein the image formingmeans comprises a plurality of heating sources for the recording body(that is to say, a multi-head), so that a same pixel can be heated bythe plurality of heating sources and if a failed heating source isproduced during writing, formation of a non-image region due tonon-heating can be prevented, thereby eliminating generation of a lineof scumming.

In the above invention, when a part of the multi-head is always heatedto produce a failed heating source and the failed heating source islocated at a marginal region, a region to be written by the failedheating source is not compensated by other heating source, so that timerequired for writing compensation is saved, thereby allowing capacity ofcontrol program to be reduced.

In the above invention, the image forming means comprises a multi-headhaving a broader recording width than that of an image formation area. Aheating failure due to too much use can be inhibited by move themulti-head in a main scanning direction each time a predeterminedprinting is carried out.

In the above structure of the apparatus according to the presentinvention, the image forming means comprises a multi-head having abroader recording width than that of an image formation area. A heatingfailure due to too much use can be inhibited by move the multi-head in amain scanning direction every predetermined period.

In the above invention, the image forming means comprises heating meansfor heating an image region and heating means for heating a marginalregion. A heating failure due to too much use can be inhibited by theabove image forming means.

In the above invention, by using the heating means for heating themarginal region comprising the multi-head having a lower resolution thanthat of the heating means for heating the image region, so that aheating time for the marginal region can be shortened, thereby reducinga time for image formation.

In the above structure of the apparatus according to the presentinvention, a resistance value of each heating source of the multi-headand/or a voltage across a resistant element connected in series with theheating source are detected to examine whether or not the failed heatingsource is present by comparing the detected voltage with a definedvoltage. If the failed heating source is generated, no formation of anon-image region by non-heating can be prevented, thereby eliminatinggeneration of a line of scumming.

In the above structure, as a negative writing means, the image formingmeans heats the recording body in a state where the recording body is incontact with an element selected from a liquid and/or a solid, therecording body having surface properties receding contact angledecreases (a liquid-attracting state) when the recording body comes intocontact with the liquid in a heated state thereof and the recedingcontact angle increases (a liquid-repelling state) when the recordingbody is heated in a non-contact state with the liquid. Alternatively,right after a surface of the recording body is heated, the surface comesinto contact with the element selected from the liquid and/or the solidto decrease the receding contact angle of the surface of the recordingbody, that is to say a liquid-attracting treatment. And then, an entirearea of the surface of the recording body becomes liquid-attractingstate and a region not to be recorded is then heated selectively by theimage forming means in the absence of the liquid and/or the solid tomake the region liquid-repelling state.

In the above structure, the image forming means comprises a plurality ofheating sources corresponding to a respective recording ink color, sothat a multi-color image can be obtained with high quality.

According to the present invention, an image forming apparatuscomprising an image forming means for forming a latent image on an imageregion of a recording body by selectively heating a non-image region ofthe recording body, wherein the image forming means has a function thata writing heat quantity can be adjusted and a heated temperature can beadjusted to prevent an irregularity of heating.

In the above structure, the image forming means has a function that thewriting heat quantity can be adjusted in response to temperatureinformation of the recording body, so that an optimal heat quantity canbe supplied based on a standard temperature of the recording body,thereby allowing a high quality image to be produced.

In the above invention, the image forming means has a function that thewriting heat quantity can be adjusted in response to heating informationof a pixel neighboring a pixel to be heated (a pixel of interest) andthe pixel written with the pixel of interest at the same time or thepixel written already, so that the influence of a temperatureirregularity on the pixel of interest in accordance with a heated stateof the neighboring pixel can be inhibited and formation of a highquality image can be carried out.

In the above structure, by using the image forming means, for the pixelof interest the writing heat quantity can be changed in accordance witha heat record of a plurality of written lines which are in the samescanning direction or are in a near position and the influence of thetemperature irregularity on the pixel of interest in response to theheat record of the written plurality of lines, thereby producing thehigh quality image.

In the above structure, the image forming means comprises the multi-headhaving a plurality of the heating source for the recording body. Bychanging the heat quantity form the multi-head in accordance with thenumber of the heating sources driving simultaneously, an irregularity ofthe heat quantity produced by the heat quantity of the heating sourcedriving simultaneously can be inhibited, thereby producing the highquality image.

In the above structure, by using the image forming means, writing can becarried out every at least other line in a sub-scanning direction, sothat accumulation of heat can be prevented during writing, thus allowingthe high quality image to be produced while suppressing the thermalirregularity.

In the above structure, a writing rate can be changed in response toimage information by use of the image forming means, so that anirregularity of accumulation of heat can be prevented during variouswriting in accordance with image information, thereby allowing the highquality image to be produced.

In the above structure, the writing rate can be changed in response toan increased temperature of the recording body by use of the imageforming means, so that an increase in the temperature of the recordingbody can be lowered during writing, thereby producing the high qualityimage.

In the above structure, image formation can be carried out by increasingthe heat quantity at an initial writing by use of the image formingmeans, so that a deficiency in the heat quantity can be prevented beforethe temperature of the recording body is stabilized, thereby producingthe high quality image.

In the above structure, the image forming means comprises the multi-headand the pixel in the same line can be recorded more than every at leastother pixel, so that accumulation of heat can be inhibited and theirregularity of heating can be eliminated to produce the high qualityimage.

In the above structure, the image forming means comprises the multi-headhaving a plurality of heating sources, each heating source being formedmore than every other pixel, so that accumulation of heat can beinhibited and the irregularity of heating can also be eliminated toproduce the high quality image.

In the above structure the image forming means comprises the multi-headand the pixel in the same line and in a spiral line can be recordedevery at least other pixel, so that accumulation of heat can beinhibited and the irregularity of heating can also be eliminated toproduce the high quality image.

In the above structure, the image forming means comprises the multi-headand the pixel in the same line can be recorded every at least otherpixel. After the last line is completed, the image forming means or therecording body is movable in the main scanning direction to continueformation of the image, so that accumulation of heat can be inhibitedand the irregularity of heating can also be eliminated to produce thehigh quality image.

In the above structure, as a negative writing means, the image formingmeans heats the recording body in a state where the recording body is incontact with an element selected from a liquid and/or a solid, therecording body having surface properties in which a receding contactangle decreases (a liquid-attracting state) when the recording bodycomes into contact with the liquid in a heated state thereof and thereceding contact angle increases (a liquid-repelling state) when therecording body is heated in a non-contact state with the liquid.Alternatively, right after a surface of the recording body is heated,the surface comes into contact with the element selected from the liquidand/or the solid to decrease the receding contact angle of the surfaceof the recording body, that is to say a liquid-attracting treatment,thereby making an entire area of the surface of the recording bodyliquid-attracting state and then a non-image region of the recordingbody is heated selectively by the image forming means in the absence ofthe contacting element, such as the liquid and/or the solid to make aregion not to be recorded the region liquid-repelling state.

In the above structure, the image forming apparatus comprises aplurality of image forming means corresponding to a respective recordingink color, so that a multi-color image can be obtained with highquality.

According to the present invention, an image forming apparatuscomprising a laser source controlled to emit laser light in response toimage information, a rotating multi-face mirror to scan the laser lightfrom the laser source, a motor to rotate the rotating multi-face mirror,and a recording body irradiated with the laser light reflected by therotating multi-face mirror, in which a latent image is formed on therecording body by irradiating the laser light in response to imageinformation, wherein the recording body is a low sensitive recordingbody comprising a light heat converting material which converts thelaser light irradiated onto the recording body to heat, the rotatingmulti-face mirror is stably rotated at a low rate with a rate reducingmeans to which the motor is rotated at a high rotation of a stablerotation region to transmit a rotating force, so that a rotation of themulti-face mirror can be stabilized to allow a scanning rate and ascanning time of the laser light to be constant and lesserirregularities of an image density, dot and a line size (for example,broadening or narrowing) can be obtained to provide an inexpensive lightscanning apparatus.

In the above invention, by providing a disk-like mass member having aweight equal to or more than that of the rotating multi-face mirror forthe motor or a rotating axis of the rotating multi-face mirror, therotation of the multi-face mirror can be stabilized at the low rate, sothat lesser irregularities of an image density, dot and a line size (forexample, broadening or narrowing) can be obtained to provide aninexpensive light scanning apparatus.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an essential structural view to explain one example of animage forming apparatus which is applicable to the present invention;

FIG. 2 illustrates an essential cross-sectional view showing anembodiment of a recording body according to the present invention;

FIG. 3 illustrates a schematic view showing a structural example inaccordance with the present invention, the structure having light-(whichincludes an electromagnetic wave) absorbing ability within the recordingbody;

FIG. 4 shows a fundamental and specific structure of a polymeric dye;

FIG. 5 illustrates an essential structural view showing one example in acase where a reflecting layer is provided within the recording body;

FIG. 6 illustrates a cross-sectional view showing one example in a casewhere a rough face is formed on a surface of the reflecting layer, thesurface being adjacent to a recording layer;

FIG. 7 illustrates a cross-sectional view of an example of a recordingbody used in a prior art, the example using a liquid;

FIG. 8 illustrates an essential structural view of a recording body toexplain an embodiment according to the present invention in a case ofusing a gel layer;

FIG. 9 illustrates an essential structural view of a recording body toexplain an embodiment according to the present invention in a case ofusing a microcapsule layer;

FIG. 10 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 11 illustrates an essential structural view to explain one exampleof a recording body according to the present invention;

FIG. 12 illustrates a cross-sectional view to explain other example ofthe recording body according to the present invention;

FIG. 13 illustrates a cross-sectional view to explain other example ofthe recording body according to the present invention;

FIG. 14 illustrates a cross-sectional view to explain other example ofthe recording body according to the present invention;

FIG. 15 illustrates a cross-sectional view to explain other example ofthe recording body according to the present invention;

FIG. 16 illustrates a cross-sectional view to explain one example of therecording body according to the present invention;

FIG. 17 illustrates an essential schematic structural view to explain anembodiment according to the present invention;

FIG. 18 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 19 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 20 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 21 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 22 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 23 illustrates a diagrammatic view to explain other embodimentaccording to the present invention;

FIG. 24 illustrates a diagrammatic view to explain other embodimentaccording to the present invention;

FIG. 25 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 26 illustrates an essential structural view to explain otherembodiment according to the present invention;

FIG. 27 shows a schematic view to explain one example in a case where awriting heat quantity is adjusted by modulating a pulse width;

FIG. 28 shows a schematic view to explain an example in a case where thewriting heat quantity is adjusted by modulating the pulse width;

FIG. 29 illustrates an essential structural view to explain an exampleto detect a temperature of the recording body;

FIG. 30 shows a schematic view to explain one embodiment according tothe present invention;

FIG. 31 shows a schematic view to explain another embodiment accordingto the present invention;

FIG. 32 illustrates a schematic structural view of a control part of aprinting machine to carry out the present invention;

FIG. 33 shows a schematic view to explain an example in a case where apixel in a main scanning direction is written at the same time,considering 3 lines written already;

FIG. 34 illustrates a schematic structural view showing a structuralexample of a printing machine to carry out the present invention;

FIG. 35 shows an essential structural view to explain other embodimentaccording to the present invention;

FIG. 36 shows an essential schematic view to explain other embodimentaccording to the present invention;

FIG. 37 shows an essential schematic view to explain other embodimentaccording to the present invention;

FIG. 38 shows an essential schematic view to explain other embodimentaccording to the present invention;

FIG. 39 illustrates a schematic view showing a relationship between amotor driven by a motor driver and a drum of a recording body, the drumbeing driven by the motor;

FIG. 40 illustrates an essential diagrammatic view to explain oneembodiment according to the present invention;

FIG. 41 illustrates a schematic view showing a relationship between amotor driven by a motor driver and a drum of a recording body, the drumbeing driven by the motor;

FIG. 42 illustrates an essential diagrammatic view to explain oneembodiment according to the present invention;

FIG. 43 shows a diagrammatic view to explain operation of the presentinvention;

FIG. 44 shows a diagrammatic view to explain other embodiment accordingto the present invention;

FIG. 45 illustrates an essential structural view to explain otherembodiment according to the resent invention;

FIG. 46 shows a diagrammatic view to explain the present invention; and

FIG. 47 illustrates an essential structural view to explain oneembodiment of a light-scanning apparatus according to the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 2 illustrates an essential cross-sectional structural view showingan embodiment of a recording body 10 according to the present invention.According to the present invention, a liquid is formed on a surface ofthe recording body 10 so as to absorb light (which includes anelectromagnetic wave) by the liquid. FIG. 2(A) shows an example in acase where the recording body 10 comprises a substrate and a recordinglayer 12 provided on the substrate, the recording layer itself being alight-absorbing element. FIG. 2(B) shows an example in a case where thelight (electromagnetic wave)-absorbing element contained within arecording layer so as to form the recording layer 13 comprising alight-absorbing element therein. FIG. 2(C) shows an example in a casewhere a light (electromagnetic wave)-absorbing layer 15 comprising thelight-absorbing element is placed between the substrate 11 and therecording layer 14. Examples of such light-absorbing elements containedin the recording layer includes those as listed in Table 1 and 2. It ispossible to use a dye and/or a pigment as the light-absorbing element.TABLE 1 1. LIGHT-HEAT CONVERTING MATERIAL TRADE ABSORPTIONCHARACTERISTICS RAW MATERIAL NAME MAKER 350˜420 nm ABOUT 1000 nm NAMEREMARKS {circle over (1)} COLOR HOYA MORE THAN 60% LESS THAN 2% GLASSMELT MIXING OF RAW FILTER TRANSMITTANCE TRANSMITTANCE MATERIAL AT THECM-500S TIME OF CASTING OF GALSS {circle over (2)} NIR KANEBO 400 nm→40%LESS THAN 3% POLYESTER HAVING A NEAR- HAVING ABSORPTION ABSORPTIONTRANSMITTANCE INFRA-RED ABSORBING IN ULTRA VIOLET FILM DYE DISPERSEDTHEREIN PORTION {circle over (3)} UGF-02 KUHEHA MORE THAN 40% LESS THAN10% ACRYLATE-BASED RESING LENTEK TRANSMITTANCE TRANSMITTANCE USING ANEAR INFRA-RED ABSORBING DYE {circle over (4)} SH-11 (T40) SUMITOMO MORETHAN 20% LESS THAN 10% THERMAL SHIELDING WHEN INCREASING A OSAKATRANSMITTANCE TRANSMITTANCE MATERIAL BASED ON THICKNESS, CEMENTINORGANIC MATERIAL ABSORPTION OF ULTRA-VIOLET PORTION BECOMES STRONG{circle over (5)} PA-1001 MITSUI 375 nm→50% λmax1110 nm METAL COMPLEXSYSTEM SAMPLE AVAILABLE TOHATSU LESS THAN 35% CHEMICAL TRANSMITTANCE{circle over (6)} IRF-1000 FUJI FILM NO λmax1000 nm NEED FORIDENTIFICATION REEXAMINATION {circle over (7)} DIINMONIUM A. C. C NOλmax1090 nm DIINMONIUM BASED- NEED FOR IDENTIFICATION COMPOUNDREEXAMINATION {circle over (8)} NK-3508 NIHON HIGH λmax1090 nm CYANINEDYE SPECTRUM OK KAKOH TRANSMITTANCE SHIKISO {circle over (9)} NKX-114NIHON LOW λmax1090 nm METAL COMPLEX SYSTEM SPECTRUM NG KAKOHTRANSMITTANCE SHIKISO

TABLE 2 TRADE ABSORPTION CHARACTERISTICS NAME MAKER 350˜420 nm ABOUT1000 nm RAW MATERIAL NAME REMARKS {circle over (10)} IRG-022 NIHON 400nm→50% LESS THAN 2% DIINMONIUM BASED- SPECTRUM OK CHEMICAL TRANSMITTANCECOMPOUND SAMPLE AVAILABLE {circle over (11)} SIR-132 MITSUI LOWTRANSMITTACNE λmax1070 nm METAL COMPLEX SYSTEM SPECTRUM NG TOHATSUSAMPLE AVAILABLE CHEMICAL {circle over (12)} CARBON ORIENT ALL SURFACEALL SURFACE BLACK CHEMICAL ABSORPTION ABSORPTION {circle over (13)} SIRBLACK MITSUI ALL SURFACE ALL SURFACE 1051M TOHATSU ABSORPTION ABSORPTIONCHEMICAL {circle over (14)} NIR-AM1 TEIKOKU LOW TRANSMITTANCE λmax1070nm METAL COMPLEX SYSTEM SPECTRUM NG CHEMICAL SAMPLE AVAILABLE SANGYO{circle over (15)} NK-2545 NIHON HIGH TRANSMITTANCE λmax1050 nm CYANINEDYE SPECTRUM OK KANKO SHIKISO {circle over (16)} NK-3509 NIHON HIGHTRANSMITTANCE λmax1050 nm CYANINE DYE SPECTRUM OK KANKO SHIKISO {circleover (17)} NK-3555 NIHON HIGH TRANSMITTANCE λmax1050 nm CYANINE DYESPECTRUM OK KAKOH SAMPLE AVAILABLE SHIKISO {circle over (18)} NK-3519NIHON HIGH TRANSMITTANCE λmax1050 nm CYANINE DYE SPECTRUM OK KAKOHSHIKISO

As a light (electromagnetic wave) generating source 1, it is suitable touse a solid laser such as YAG laser, a semiconductor laser and a LEDarray. As a method for scanning light to the surface of the recordingbody, use is preferably made of the method based on a raster scanningwith a polygon mirror and a galvano mirror, and the scanning method withrotating the recording body. It is preferable to use a shorterwavelength of the light (electromagnetic wave), so that a spot sizeirradiated by the source 1 becomes smaller to obtain a high resolution.

[Example]

Functional material having the thermal changeable character ofwettability

Acrylate-based polymer containing a fluorine atom

-   Substrate: Polyester film-   Light (electromagnetic wave)-absorbing material Cyanine-based dye-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine dye    was added in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Result: An image recording could be accomplished with one-tenth of    an irradiation energy, as compared to a conventional material    system.

FIG. 3 illustrates a schematic view showing a structural example of therecording body 10 having light-absorbing ability shown in FIG. 1. Inthis figure, A part is a site having the thermal changeable character ofwettability and B part is a site having the light (electromagneticwave)-absorbing ability. As shown in FIG. 3, as the recording bodyitself having the electromagnetic wave absorbing ability, it ispreferable to use a coplymer comprising a monomer having the changeablecharacter of wettability such as the polymer disclosed in JapaneseLaid-Open Patent Application No. 3-178478, and a monomer having askeleton structure of the dye as a side chain, so-called a polymericdye.

FIG. 4 shows examples of the polymeric dyes described above. Basically,as shown in FIG. 4(A), a structure of the polymeric dye is based on avinyl monomer, that is to say, the vinyl monomer having the dye as theside chain. More specifically, it is possible to use the monomer havingthe structure as shown in FIG. 4(A), 4(B) and 4(C).

[Example]

Functional material having the thermal changeable character ofwettability: Copolymer comprising an acrylate-based polymer containingthe fluorine atom

-   Substrate: Polyimide film-   Light (electromagnetic wave)-absorbing material

Monomer having a phthalocyanine-based dye as a pendant group.

-   Layer structure: Copolymer comprising the acrylate-based monomer    containing the fluorine atom and the above monomer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Result: An image recording could be accomplished with one-twentieth    of the irradiation energy, as compared to the conventional material    system.

Alternatively, it is possible to use the dye or pigment dissolved ordispersed in the recording layer, the dye or pigment absorbing incidentlight into the recording layer. In this case, the recording layercontains the recording layer material and the absorbing materialseparately. This results in a wide selection of each material. It ispreferable to contain a concentration of from 10 wt % to 30 wt % in acase of the pigment, and from 1 wt % to 10 wt % in a case of the dye.

[Example]

Functional material having the thermal changeable character ofwettability

Acrylate-based polymer containing the fluorine atom.

-   Substrate: Polyester film-   Light (electromagnetic wave)-absorbing material

Cyanine-based pigment (A particle size is 0.1 μm).

-   Layer structure: A content of 10 wt % to 50 wt % of the    cyanine-based pigment was dispersed within the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Result: An image recording could be accomplished with one-eighth of    the irradiation energy, as compared to the conventional material    system.

Further, a reflection layer is provided between the substrate and therecording layer containing the material having the changeable characterof wettability so that multiple reflections tales place within therecording layer. This allows an optical path length of light tolengthen, thereby improving an efficiency of the light-heat conversion.

Referring to FIG. 5, as stated above, the reflection layer 16 reflectslight (electromagnetic wave) L repeatedly so that the length of theoptical path can be increased. This results in improvement of thelight-heat conversion efficiency. As the reflecting layer, it isdesirable to use the substrate 11 deposited with aluminum and thesubstrate 11 coated or deposited with a white oxide, for exampletitanium oxide and aluminum oxide or the like. Alternatively, it ispossible to use a primer provided on a surface of the reflecting layer16 in order to avoid that a contact strength may be deteriorated betweenthe recording layer 17 and the primer.

[Example]

Functional material having the thermal changeable character ofwettability:

Acrylate-based polymer containing the fluorine atom.

-   Substrate: Polyester film-   Light (electromagnetic wave)-absorbing material Cyanine-based dye.-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine-based    dye was contained in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Reflection layer: Aluminum was deposited on the substrate with a    thickness of 1000 Å.-   Result: An image recording could be accomplished with one-twentieth    of the irradiation energy, as compared to the conventional material    system.

Referring to FIG. 6, a rough surface 16A is formed on a surface of thereflecting layer, the surface being adjacent to the recording layer, sothat light is scattered at the rough surface 16A. An even penetration oflight can be improved by the light scattering at the rough surface. Itshould be noted that a roughness of the surface of the reflecting layer16 is from 0.1 μm to 10 μm, this value being defined as Rz.

[Example]

Functional material having the thermal changeable character ofwettability: Acrylate-based polymer containing the fluorine atom.

-   Substrate: Polyester film-   Light (electromagnetic wave)-absorbing material Cyanine-based dye.-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine-based    dye was contained in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Reflection layer: Aluminum was deposited on the substrate having the    roughness of 0.1 μm defined as Rz with the thickness of 1000 Å.-   Result: An image recording could be accomplished with one-twentieth    of the irradiation energy, as compared to the conventional material    system.

Japanese Laid-Open Patent Application No. 8-276663 discloses a methodfor negative writing in which there are the drawbacks that a lifetime ofa light source tends to shorten as compared to positive writing, sincethe light source is operated continuously. Because of this, it isnecessary to lengthen the lifetime of the light source, to cope witheasiness of holding the liquid layer and supply of the liquid, to ensurestability of supply and storage of the liquid, and to facilitate highrate writing, as positive writing.

As shown in FIG. 7, the recording body comprises the substrate 11 andthe recording layer 12. The liquid layer W is formed on the recordinglayer 12 by a liquid layer forming means 9. The recording body 10 hassurface characteristics in which when a surface of the recording body 10is brought into contact with the liquid, a receding contact angledecreases (a liquid-attracting state), or when the surface of therecording body 10 is heated in a non-contact state with the liquid, thereceding contact angle increases (a liquid-repelling state). An onlyimage region is heated in a contact state with an element selected fromthe liquid and/or a solid, or right after the surface of the recordingbody is heated, the surface is selectively brought into contact with theelement selected from the liquid and/or the solid, so as to form alatent image on the recording body. The latent image is developed bymeans of an inking unit 3 to form an image, and the image is thentransferred through a transfer roller 4 or is recorded directly into arecording paper 5. The light (electromagnetic wave) generating apparatusis used as heating means 1 and heating is carried out in the non-contactstate with the recording body.

As a method for forming the liquid layer W on the recording body, it ispossible to coat the liquid or to attach a film containing the liquid orthe like. As the liquid for use in the liquid layer W, it is possible touse a liquid having a non-repelling property on the recording body 10,for example a liquid having a surface energy near that of the recordingbody 10, an ink solvent (this solvent has the advantages that it isunnecessary to remove the liquid layer after writing), a viscous liquidcontaining water and a water-soluble resin (polyvinyl alcohol, polyvinylpyrrolidone or the like) or the like.

Formation of the liquid layer W and irradiation of light(electromagnetic wave) L are carried out by pre-forming the liquid layerW on the surface of the recording body 10 followed by irradiating thelight (electromagnetic wave) L, or pre-irradiating the light(electromagentric wave) followed by forming the liquid layer W on thesurface of the recording body 10 while using a residual heat.Alternatively, Formation of the liquid layer W and irradiation of thelight (electromagnetic wave) L are carried out simultaneously.

[Example]

-   Substrate: Polyester film-   Functional material having the thermal changeable character of    wettability:

Acrylate-based polymer containing the fluorine atom.

-   Light (electromagnetic wave)-absorbing material Cyanine-based dye.-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine-based    dye was contained in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Means for supplying the liquid layer: Coating on the surface of the    recording body by means of a porous elastic roller impregnated with    an involatile solvent of the ink.-   Result: A positive image recording could be accomplished at a high    rate.

FIG. 8 illustrates an essential structural view of the recording body toexplain other embodiment according to the present invention. In thisembodiment, a gel layer 18 is formed on the surface of the recordinglayer 12 of the recording body 10 and recording can be carried out byirradiating the light (electromagnetic wave) L onto the gel layer 18.More specifically, by using a gel-like element having a sol-geltransition property, once the gel-like element makes sol to haveliquidity and the sol is then coated on the recording body 10, so thatthe sol is again subjected to gelation treatment to achieve recording.

[Example]

-   Substrate: Polyester film-   Functional material having the thermal changeable character of    wettability

Acrylate-based polymer containing the fluorine atom.

-   Light (electromagnetic wave)-absorbing material: Cyanine-based dye.-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine-based    dye was contained in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm. Means for supplying the liquid layer: Contact    of the gel, such as gelatin and the like with the recording body    followed by removal after heating. Result: The liquid layer was    easily held on the recording body.

FIG. 9 illustrates an essential structural view of the recording body toexplain other embodiment according to the present invention. In thisfigure, a microcapsule layer is designated 19. In this embodiment, as afunctional material having the thermal changeable character ofwettability, the microcapsule layer 19 is included in the liquid and amicrocapsule contained in the microcapsule layer 19 is broken down bymeans of thermal energy at the time of irradiation of light(electromagnetic wave) so as to form the liquid layer on the surface ofthe recording body 10. It should be noted that in this case, it isdesirable to contain the light (electromagnetic wave)-absorbing agent onthe surface of or inside the microcapsule.

[Example]

-   Substrate: Polyester film-   Functional material having the thermal changeable character of    wettability

Acrylate-based polymer containing the fluorine atom.

-   Light (electromagnetic wave)-absorbing material

Cyanine-based pigment (the particle size is 0.1 μm).

-   Layer structure: A content of 10 wt % to 50 wt % of the    cyanine-based pigment was dispersed in the recording layer.-   Light (electromagnetic wave) source: Semiconductor laser having a    wavelength of 800 nm.-   Means for supplying the liquid layer: A microcapsule particulate    based on polyethylene contained in the involatile solvent of the    ink.-   Result: Supply of the liquid and stability for storage of the liquid    could be ensured.

FIG. 10 illustrates en essential structural view to explain otherembodiment according to the present invention. Referring to FIG. 10, theimage forming apparatus comprises a light (electromagneticwave)-generating device 1, a rotating drum 2, a film 21, means forsupplying the liquid 22 and a film cutter 23. In this embodiment, asshown in FIG. 10, the film 21 is wound around the rotating drum 2 whileplacing the liquid on the film 21 by means 22 so as to form the liquidlayer on the recording body 10 on the rotating drum 2. It should benoted that use is made of the film 21 having the light (electromagneticwave) transmissible property. An uniform thin layer of the liquid phasecan be formed by placing the liquid between the films, so that unevenheating can be avoided to achieve the image formation without anirregularity.

[Example]

-   Substrate: Polyester film-   Functional material having the thermal changeable character of    wettability

Acrylate-based polymer containing the fluorine atom.

-   Light-(electromagnetic wave) absorbing material

Cyanine-based base.

-   Layer structure: A content of 1 wt % to 10 wt % of the cyanine-based    dye was contained in the recording layer. Light (electromagnetic    wave) source Semiconductor, laser having a wavelength of 800 nm.

Means for supplying the liquid layer: Inclusion of the recording body bya polyester film while supplying the involatile solvent of the ink atthe time of recording. Result: Writing could be accomplished at the highrate and the image formation could also be performed without theirregularity.

However, as shown in FIG. 11(A), a recording body 30 comprises arecording layer 31, a light-heat converting layer 32 and a base body 33.It should be noted in the following description that the light-absorbingelement is not necessarily contained in the recording body 30. Asheating means, for example in a case of writing by means of a laser,when incident light passes through the recording layer 31 and thelight-heat converting layer 32 from a surface of the recording layer 31the recording so as to reflect the light at a surface of the substratebody 33, a regular reflection is strong and the reflected light arrivesat a boundary face between the light-heat converting layer 32 and therecording layer 31 or the surface of the recording layer 31. Thisreflected light is again reflected at each boundary face and the surfaceand the like, so that multi-reflection takes place within each layer,thereby giving rise to problems relating to spreading of an exposedregion and the irregular recording, such as a moire. In a method forexposing an image region, that is to say, a positive writing method, byspreading of the exposed region is meant spreading of the image region,while in a method for exposing a non-image region, that is to say, anegative writing method, by spreading of the exposed region is meantnarrowing of the image region. Since increasing the number of the layerresult in an increased cost, problems to be solved in the presentinvention is to provide the recording body having the number of thelayer as limited as possible.

Also, as shown in FIG. 12(A), the recording body 30 comprises arecording layer 34 having the light-heat converting agent dispersedtherein and a base body 33. As heating means, for example in a case ofwriting by means of the laser, when incident light from a surface of therecording layer 34 passes through the recording layer 34 and the lightis reflected at a surface of the base body 33, a regular reflection isstrong and the reflected light arrives at the surface of the recordinglayer 34. This results in multi-reflection within the recording layer34, thereby presenting the problems regarding spreading of the exposedregion and the irregular recording, such as the moire. In a method forexposing an image region, by spreading of the exposed region is meantspreading of the image region, while in a method for exposing anon-image region, by spreading of the exposed region is meant narrowingof the image region. Since increasing the number of the layer result inan increased cost, problems to be solved in the present invention is toprovide the recording body having the number of the layer as limited aspossible.

Further, in another recording body other than the above structure, forexample the recording body may comprise the recording layer, thelight-heat converting layer and a transparent base body. When incidentlight from the surface of the recording body passes through therecording layer, the light-heat converting layer and the transparentbase body, and the light is reflected at a back surface of thetransparent base body, a regular reflection is strong and the reflectedlight arrives at a boundary face between the transparent base body andthe light-heat converting layer, a boundary face between the light-heatconverting layer and the recording layer, or the surface of therecording body. This results in multi-reflection within each layer, asstated above, thereby presenting the problems regarding spreading of theexposed region and the irregular recording, such as the moire. Inaddition, there may be arisen the problem to be solved that therecording body is required to produce as cheap as possible.

Furthermore, the recording body may comprise a recording layer havingthe light-heat converting agent dispersed therein and the transparentbase body. When incident light from the surface of the recording layerpasses through the recording layer and the transparent base body and thelight is reflected at the back surface of the transparent base body, theregular reflection is strong and the reflected light arrives at theboundary face between the transparent base body and the recording layeror the back surface of the recording layer. This results inmulti-reflection within each layer, as mentioned above, therebypresenting the problems regarding spreading of the exposed region andthe irregular recording, such as the moire. In addition, there may bearisen the problem to be solved that the recording body is required toproduce as cheap as possible.

Moreover, a carrier of the recording body carries the recording bodycomprising the recording layer, the light-heat converting layer and thetransparent base body. In this case, when incident light from thesurface of the recording layer passes through the recording layer, thelight-heat converting layer and the transparent base body and the lightis reflected at a surface of the carrier of the recording body, aregular reflection is strong and the reflected light arrives at theboundary face between the transparent base body and the light-heatconverting layer, the boundary face between the light-heat convertinglayer and the recording layer, or the surface of the recording layer.This results in multi-reflection within each layer, thereby presentingthe problems regarding spreading of the exposed region and the irregularrecording, such as the moire.

Similarly, the recording body may comprise the recording layer havingthe light-heat converting agent dispersed therein and the transparentbase body. In this case, when incident light from the surface of therecording layer passes through the recording layer and the transparentbase body and the light is reflected at the surface of the carrier ofthe recording body, an regular reflection is strong and the reflectedlight arrives at the boundary face between the transparent base body andthe light-heat converting layer, or the surface of the recording layer.This results in multi-reflection within each layer, thereby presentingthe problems regarding spreading of the exposed region and the irregularrecording, such as the moire.

According to the present invention, spreading of the exposed region canbe reduced and widening and narrowing of imaged areas can be compensatedwith the recording body comprising the recording layer, the light-heatconverting layer and the base body, the recording body comprising therecording layer having the light-heat converting agent dispersed thereinand the base body, the recording body comprising the recording layer,the light-heat converting layer and the transparent base body, therecording body comprising the recording layer having the light-heatconverting agent dispersed therein and the transparent base body, therecording body comprising the recording layer carried on a carrier ofthe recording body, the light-heat converting layer and the transparentbase body, and also the recording body comprising the recording layerwhich is carried on the carried of the recording body and has thelight-heat converting agent dispersed therein, and the transparent basebody.

FIG. 11(A) shows a cross-sectional view to explain an embodiment of therecording body which is applicable to the present invention. Therecording body 30 comprises the recording layer 31, the light-heatconverting layer 32 and the base body 33. As mentioned above, when theincident light from the surface of the recording layer 31 passes throughthe recording layer 31 and the light-heat converting layer 32 and thelight is reflected at the surface of the base body 33, the regularreflection is strong and the reflected light arrives at the boundaryface between the light-heat converting layer 32 and the recording layer31, or the surface of the recording layer 31. This results inmulti-reflection within each layer, thereby presenting the problemsregarding spreading of the exposed region and the irregular recording,such as the moire.

FIG. 11(B) shows a cross-sectional view of one embodiment of therecording body 30 according to the present invention. A layer 35preventing the regular reflection of the incident light which is usedfor recording is provided between the base body 33 and the light-heatconverting layer 32 of the recording body 30. As the layer 35 preventingthe regular reflection, for example a light-diffusing layer is used,which comprises a binder and a fine particle (TiO₂, MgO) dispersedtherein. This allows the regular reflection where the light is reflectedat the surface of the base body 303 to be weakened, so thatmulti-reflection can be eliminated within each layer. This amelioratesthe problems relating to spreading of the exposed region and theirregular recording, such as the moire.

FIG. 11(C) shows a cross-sectional view to explain other embodiment ofthe recording body according to the present invention. In this figure,an uneven structure 33 a is provided on a surface side of the light-heatconverting layer 32 of the base body 33. This structure 33 a causes theregular reflection of the incident light which is used for recording tobe prevented. However, as shown in FIG. 11(B), increasing the number oflayer results in high cost. Thus, as shown in FIG. 11(C), by providingthe uneven structure 33 a on the surface side of the light-heatconverting layer 32 of the base body, the regular reflection can beweakened when the incident light is reflected at the surface of the basebody 33, so that multi-reflection can be inhibited within each layer andthe problems can be improved with respect to spreading of the exposedregion and the irregular recording, such as the moire. In addition,without increase in the number of layers the recording body can beproduced inexpensively. It should be noted that a roughness of the evenstructure is in a range of from 0.11 to 1.0 μm.

FIG. 12(A) shows a cross-sectional view to explain an embodiment of therecording body which is applicable to the present invention. In thisfigure, the recording body 30 comprises the recording layer having thelight-heat converting agent dispersed therein and the base body 33. Asstated above, when the incident light from the surface of the recordinglayer 34 passes through the recording layer 34 and the light isreflected at the surface of the base body 33, the regular reflection isstrong and the reflected light arrives at the surface of the recordinglayer 34. This results in multi-reflection within each layer, so thatthere may be arisen the problems relating to spreading of the exposedregion and the uneven recording, such as the moire.

FIG. 12(B) shows a cross-sectional view of an embodiment of therecording body 30 according to the present invention. As shown in FIG.12(B), the recording body 30 comprises the base body 33, the recordinglayer 34 having the light-heat converting agent dispersed therein and alayer 35 preventing the regular reflection of the incident light whichis used for recording are placed between the recording layer 34 and thebase body 33. As the layer 35, the light-diffusing layer is used, whichcomprises the binder and the fine particle (TiO₂, MgO) dispersedtherein. This allows the regular reflection where the light is reflectedat the surface of the base body 33 to be weakened, so thatmulti-reflection can be eliminated within each layer. This amelioratesthe problems relating to spreading of the exposed region and the unevenrecording, such as the moire.

FIG. 12(C) shows a cross-sectional view to explain other embodiment ofthe recording body according to the present invention. In this figure,an uneven structure 33 a is provided on the surface of the light-heatconverting layer 34 of the base body 33. This structure 33 a causes theregular reflection of the incident light which is used for recording tobe prevented. However, as shown in FIG. 12(B), increasing the number oflayer results in high cost. Thus, as shown in FIG. 12(C), by providingthe uneven structure 33 a on the surface of the base body 33, theregular reflection can be weakened when the incident light is reflectedat the surface of the base body 33, so that multi-reflection can beinhibited within each layer and the problems can be improved withrespect to spreading of the exposed region and the irregular recording,such as the moire. In addition, without increase in the number of layersthe recording body can: be produced inexpensively. It should be notedthat the roughness of the uneven structure is in a range of from 0.1 to1.0 μm.

FIG. 13(A) shows a cross-sectional view to explain other embodiment ofthe recording body which is applicable to the present invention. In thisfigure, the recording body 30 comprises the transparent base body 36,the light-heat converting layer 32 and the recording layer 31. As statedabove, when the incident light from the surface of the recording layer31 passes through the recording body 30, the light-heat converting layer32 and the transparent base body 36 and the light is reflected at theback surface of the transparent base body 36, the regular reflection isstrong and the reflected light arrives at the boundary face between thetransparent base 36 and the light-heat converting layer 32, the boundaryface between the light-heat converting layer and the recording layer 31,or the surface of the recording layer 31. This results inmulti-reflection within each layer, so that there may be arisen theproblems relating to spreading of the exposed area and the irregularrecording, such as the moire.

FIG. 13(B) shows a cross-sectional view to explain an embodimentaccording to the present invention. In this figure, the recording body30 further comprises a layer 35 preventing the regular reflection of theincident light which is used for recording. As the layer 35, thelight-diffusing layer is used, which comprises the binder and the fineparticle (TiO₂, MgO) dispersed therein. This allows the regularreflection where the light is reflected at the surface of the base body33 to be weakened, so that multi-reflection can be eliminated withineach layer. This ameliorates the problems relating to spreading of theexposed region and the irregular recording, such as the moire.

FIG. 13(C) shows a cross-sectional view to explain other embodimentaccording to the present invention. In this figure, an uneven structure36 a is provided on an opposite side surface of the base body 36 to thelight-heat converting layer 32. This structure 36 a causes the regularreflection of the incident light which is used for recording to beinhibited. However, as shown in FIG. 13(B), increasing the number oflayer may result in high cost. According to the present invention, theproblems to be solved is to provide the even structure on the oppositeside of the base body 36 to the light-heat converting layer 32. Theroughness of the uneven structure is in a range of from 0.1 to 1.0 μm.Thus, the regular reflection can be weakened when the incident-light isreflected at the surface of the transparent base body, so thatmulti-reflection can be inhibited within each layer and the problems canbe improved with respect to spreading of the exposed region and theirregular recording, such as the moire. In addition, without increase inthe number of layers the recording body can be produced inexpensively.

FIG. 14(A) shows a cross-sectional view to explain other embodiment ofthe recording body which is applicable to the present invention. In thisfigure, the recording body 30 comprises the transparent base body 36 andthe recording layer 34 having the light-heat converting agent dispersedtherein. In this structure, when the incident light from the surface ofthe recording layer 34 passes through the recording layer 34 and thetransparent base body 36 and the light is reflected at the back surfaceof the transparent base body 36, the regular reflection is strong andthe reflected light arrives at the boundary face between the transparentbase body 36 and the recording layer 34 or the recording layer 34. Thisresults in multi-reflection within each layer, so that there may bearisen the problems relating to spreading of the exposed area and theirregular recording, such as the moire.

FIG. 14(B) shows a cross-sectional view to explain an embodimentaccording to the present invention. As shown in FIG. 14(B), therecording body 30 further comprises a layer 35 preventing the regularreflection of the incident light which is used for recording, the layer35 being arranged in the opposite side of the transparent base body 36to the recording layer 34. As the layer 35, the light-diffusing layer isused, which comprises the binder and the fine particle (TiO₂, MgO)dispersed therein. This allows the regular reflection where the light isreflected at the back surface of the transparent base body 36 to beweakened, so that multi-reflection can be eliminated within each layer.This ameliorates the problems relating to spreading of the exposedregion and the irregular recording, such as the moire.

FIG. 14(C) shows a cross-sectional view to explain other embodimentaccording to the present invention. In this figure, an uneven structure36 a is provided on the opposite side of the transparent base body 36 tothe recording layer 34. This structure 36 a causes the regularreflection of the incident light which is used for recording to beinhibited. However, as shown in FIG. 14(B), increasing the number oflayer may result in high cost. According to the present invention, theproblems to be solved is to provide the even structure on the oppositesurface of the recording layer 34 of the transparent base body 36. Theroughness of the uneven structure is in a range of from 0.1 to 1.0 μm.Thus, the regular reflection can be weakened when the incident light isreflected at the surface of the transparent base body 36, so thatmulti-reflection can be inhibited within each layer and the problems canbe improved with respect to spreading of the exposed region and theirregular recording, such as the moire. In addition, without increase inthe number of layers the recording body can be produced at low cost.

FIG. 15(A1) shows an essential cross-sectional structural view of arecording apparatus which is applicable to the present invention. Inthis figure, the recording body 30 comprises the transparent base body36, the light-heat converting layer 32 and the recording layer 31. Acarrier of the recording body 40 carries the recording body 30. Forexample, in a case where the recording body 30 is carried on the carrierof the recording body 40 by means of the recording body roller 2 asshown in FIG. 1, when the incident light from the surface of therecording layer 31 passes through the recording layer 31, the light-heatconverting layer 32 and the transparent base body 36, and the light isreflected at a surface of the carrier of the recording body 40, theregular reflection is strong and the reflected light arrives at theboundary face between the transparent base body 36 and the light-heatconverting layer 32, the boundary face between the light-heat convertinglayer 32 and the recording layer 31, or the surface of the recordinglayer 31. This results in multi-reflection within each layer, therebypresenting the problems relating to spreading of the exposed area andthe irregular recording, such as the moire. By spreading of the exposedarea is meant spreading of the image area in the case of the method forexposing the image region, while by spreading of the exposed area ismeant narrowing of the image region in the case of the method forexposing the non-image region.

FIG. 15(B1) shows an essential cross-sectional structural view toexplain other recording apparatus which is applicable to the presentinvention. A carrier of the recording body 40 carries the recording body30 comprising the transparent base body 36 and the recording layer 30having the light-heat converting agent dispersed therein. For example,in a case where the recording body 30 is carried on the carrier of therecording body 40 by means of the recording body roller 2 as shown inFIG. 1, when the incident light from the surface of the recording layer34 passes through the recording layer 34 and the transparent base body36, and the light is reflected at a surface of the carrier of therecording body 40, the regular reflection is strong and the reflectedlight arrives at the boundary face between the transparent base body 36and the recording layer 34 or the surface of the recording layer 34.This results in multi-reflection within each layer, thereby presentingthe problems relating to spreading of the exposed area and the irregularrecording, such as the moire. By spreading of the exposed area is meantspreading of the image area in the case of the method for exposing theimage region, while by spreading of the exposed area is meant narrowingof the image region in the case of the method for exposing the non-imageregion.

FIG. 15(A2) and FIG. 15(B2) show essential cross-sectional structuralviews to explain embodiments according to the preset invention,respectively. As shown in these figures, the present invention providesthe layer 35 preventing the regular reflection of the incident lightinto the surface of the carrier of the recording body 40. As the layer35, the light-diffusing layer is used, which comprises the binder andthe fine particle (TiO₂, MgO) dispersed therein. Thus, the regularreflection can be weakened when the incident light is reflected at thesurface of the carrier of the recording body 40, so thatmulti-reflection can be inhibited within each layer and the problems canbe improved with respect to spreading of the exposed region and theirregular recording, such as the moire.

FIG. 15(A3) and FIG. 15(B3) show essential cross-sectional structuralviews to explain embodiments according to the preset invention,respectively. In these figures, the uneven structure 40 a is provided onthe surface of the carrier of the recording body 40. The roughness ofthe uneven structure is in a range of from 0.1 to 1.0 μm. Thus, theregular reflection can be weakened when the incident light is reflectedat the surface of the carrier of the recording body 40, so thatmulti-reflection can be inhibited within each layer and the problems canbe improved with respect to spreading of the exposed region and theirregular recording, such as the moire. In addition, without increase inthe number of layers the recording body can be produced at low cost.

As explained above, after pressing a desired run, the recording body 10or 30 is reused upon removal of the ink remaining on the recording body.If an amount of the ink remaining on the body is small in this case, itis easy to remove the ink. If the recording body has the rough surfacein a case where the surface of the recording body is washed, apigment-based ink is likely to remain on recess portion of the surface.So, by smoothing the surface of the recording body, more specifically,an amount of the remaining pigment can be reduced by making the surfaceof the recording body having roughness of less than 20 μm, preferablyless than 10 μm. Because the recording body according to the presentinvention has the smooth surface thereof, it is easy to wash the surfaceof the recording body due to the small amount of the remaining ink onthe surface of the recording body.

When the surface of the recording body is brought into contact with anymembers, a scratch is generated on the surface, so that function of thescratched portion of the surface is deteriorated as the recording body,thereby giving rise to problems relating to scumming and an area not tobe recorded at the scratched site. Alternatively, in a case where thefunction of the scratched portion is kept even when scratched, thepigment contained in the ink is likely to remain at the scratched site,so that the scratched site may be causative factor in the scumming. Inorder to avoid this, the scratch is unlikely to generate by enhancing ahardness of the recording layer. More specifically, it is preferable forthe hardness of the recording layer to have more than H hardness as apencil hardness, more preferably more than 2H hardness, so that thescratch is unlikely to generate on the surface of the recording body.

In addition, by providing elasticity for the recording layer of therecording body, the scratch is unlikely to generate on the surface ofthe recording body because of relaxation of a stress applied on thesurface of the recording body. Additionally, when the above recordinglayer has a thickness of more than predetermined value, the scratch isfurther unlikely to generate on the surface. More specifically, aYoung's modulus of the recording layer is preferably equal to or lessthan 1.0×10⁷ N/m², more preferably equal to or less than 0.5×10⁷ N/m²,and the thickness of the recording layer is preferably equal to or morethan 2 μm, more preferably equal to or more than 4 μm.

Furthermore, when a substrate of the recording body has elasticity of apredetermined value, the scratch is also unlikely to generate on thesurface of the recording body because of relaxation of the stressapplied on the surface of the recording body. Additionally, when theabove recording layer has the thickness of more than predeterminedvalue, the scratch is further unlikely to generate on the surface. Morespecifically, the Young's modulus of the substrate 11 is preferablyequal to or less than 1.0×10⁸ N/m², more preferably equal to or lessthan 1.0×10⁸ N/m², and the thickness of the substrate 11 is preferablyequal to or more than 25 μm, more preferably equal to or more than 50μm.

As shown in FIG. 16, by providing a cushion layer 38 having elasticitybetween the recording layer 31 (or 34) of the recording body 30 and thebase body 33, the scratch is also unlikely to generate on the surface ofthe recording body because of relaxation of the stress applied on thesurface of the recording body. In addition, when the cushion layer 38has the thickness of more than a predetermined value, the scratch isalso unlikely to generate on the surface of the recording body. Morespecifically, the Young's modulus of the cushion layer 38 is preferablyequal to or less than 8.0×10⁷ N/m², more preferably equal to or lessthan 2.5×10⁷ N/m²; and the thickness of the cushion layer 38 ispreferably equal to or more than 5 μm, more preferably equal to or morethan 10 μm.

As explained above, after the printing the desired press run by use ofthe recording body according to the present invention, the image formedon the recording body is removed to form a new image on the recordingbody, so that the recording body can be reused repeatedly. However, whenthe recording body used once is reused again, the remaining ink on therecording body must be washed after using previously. If not, theremaining ink prevents the following image from forming on the recordingbody.

As mentioned above, after the printing for the desired press run iscarried out with the recording body 10 (or 30), the latent image(liquid-attracting region) produced on the recording body is removed andthe ink remaining on the recording body is also removed, so that a newimage can be formed on the recording body so as to reuse the recordingbody. The removal means for removing the remaining ink may beincorporated into the image forming apparatus. The removal means may bedetachable from the recording body roller 2, or the removal means may bedetachable from the image forming apparatus together with the recordingbody.

According to the present invention, as stated above, after printing thedesired press run, the recording body is coated a liquid which iscompatible with a resin and the pigment contained in the ink forrecording, or the recording body is immersed in the liquid whichexhibits compatibility with the resin and the pigment. And then, thepigment-based ink and the resin on the recording body are wiped by meansof a waste or the like, together with the above liquid. As the liquidwhich shows compatibility with the resin and the pigment used for ink,it is possible to use aliphatic hydrocarbon, aromatic hydrocarbon,ketones, alcohols, a polar solvent, a non-polar solvent or the like.More specifically, a blanket cleaner which is commercially available iscoated on the recording body 10 developed already and the ink is wipedby means the waste or the like to remove the ink.

According to other embodiment of the present invention, after theprinting is completed, the involatilizable or volatilizable solventwhich are contained in the ink is coated on the recording body and theink is wiped with the waste or the like, so that the pigment-based inkand the resin can be removed effectively. The solvent for coating can beselected according to the solvent contained in the ink to be removed,for example paraffin and olefin solvent. More specifically, solvent No.6 (This is paraffin solvent), which is frequently used for ink solvent,is coated on the recording body developed already and the ink can bewiped with the waste or the like so as to remove the ink.

The liquid which exhibits compatibility with the resin and the pigmentcontained in the ink for recording, or the involatilixable orvolatilizable solvent which is contained in the ink for recording iscoated on the recording body after printing, or the recording body isimmersed in the above liquid or solvent and the recording body is thensubjected to supersonic treatment. By means of non-contact means, thesurface of the recording body is washed to remove the remaining ink.More specifically, the recording body developed already is immersed in aliquid of the blanket cleaner and the ink remaining on the recordingbody is removed by means of a supersonic washing machine, so that theink can be removed without the scratch on the recording body.

In addition, after removal of the remaining ink, the surface of therecording body is washed to completely remove the pigment and thesolvent for ink and a cleaning liquid, which are remaining on thesurface thereof. For example, after removal of the ink, a residualmaterial on the surface of the recording body, such as water and asurfactant or the like, are completely removed and the surface is washedwith a liquid which does not remain on the surface of the recordingbody. More specifically, after removal of the ink by the above method,the surface of the recording body is washed with a 10 wt % solution ofthe surfactant containing a fluorine atom, such as surfron (AsahiChemical Co. Ltd).

As stated above, after printing the desired press run, the ink remainingon the recording body is removed to reuse the recording body again. Inthis case, small amount of the remaining ink thereon facilitates removalof the remaining ink.

In order to remove the remaining ink after printing, the ink remainingon the surface of the recording body can be easily removed by contactinga adhesive member with the surface of the recording body. As theadhesive member, it is possible to use a single member havingadhesiveness itself, or a composite member having a coating of anadhesive tape or an adhesive agent on a NBR rubber. More specifically, aisobutyl rubber roller comes into contact with the surface of therecording body to remove the ink.

In another embodiment according to the present invention, when a memberhaving a surface roughness more than that of the recording body isbrought into contact with the surface of the recording body developedalready, the remaining ink on the surface of the recording body can beeasily removed. In this case, it is preferred that the member has thesurface roughness more than that of the surface of the recording body.More specifically, in a case where the recording body has the surfaceroughness of 10 μm, when the member has the surface roughness of 20 μm,the ink can be removed,

In other embodiment according to the present invention, a solid film isformed on the surface of the recording body developed already and thesolid film is removed together with the ink to easily remove the inkremaining on the surface of recording body. In this case, a liquid iscoated, from which the solid film is formed in the absence of water.After drying, the remaining ink can be removed with the film. Morespecifically, a 2 wt % aqueous solution of polyvinyl alcohol (POVAL) iscoated on the surface of the recording body. After drying, a film ofPOVAL can be removed with the ink.

In other embodiment according to the present invention, after theresidual material is air-dried on the surface of the recording body tocure it completely, removal of the dried ink can be carried out by theabove method, so that the ink can be removed easily and effectively.More specifically, after printing, the ink remaining on the surface ofthe recording body is allowed to stand until the ink is curedcompletely, for example, standing for 3 to 4 hours, and the isobutylrubber is then brought into contact with the ink to remove it.

Alternatively, after the ink remaining on the surface of the recordingbody developed already is cured compulsorily, removal of the cured inkis easily accomplished by the above method for a short time. Morespecifically, after the ink remaining on the recording body iscompletely cured by a compulsory means, such as heating fixation,silicone fixing method or the like, a silicone rubber is brought intocontact with the surface of the recording body developed already. Thesolution of POVAL is then coated on the surface to form a film of POVALby drying. The film can be removed with the ink.

In the image forming apparatus as stated above, negative writing for theimage formation is carried out by heating the non-image region. If theheating element or energy radiation source of the image formingapparatus is broken down, a broken portion of the element or the sourcedoes not work to generate a line of scumming, thereby giving rise toproblems relating to dramatic image degradation. In order to solve theseproblems, other heating body or other energy radiation source iscompensated for the broken element.

FIG. 17 illustrates an essential schematic structural view to explain anembodiment according to the present invention. The image formingapparatus includes the recording body roller 2, the recording body. 10(or 30), a multi-head 50. At the time of recording, that is to say,image formation, the recording body rotates in a direction shown by anarrow A and the multi-head 50 is movable gradually in a direction shownby an arrow B. According to the present invention, the recording bodyhas the surface properties that the receding contact angle decreases(the liquid-attracting state) when the recording body comes into contactwith the liquid in a heated state thereof and the receding contact angleincreases (the liquid-repelling state) when the recording body is heatedin a non-contact state with the liquid. The image forming meansaccording to the present invention heats the recording body in the statewhere the recording body is in contact with the element selected fromthe liquid and/or the solid. Alternatively, right after the surface ofthe recording body is heated by the image forming means, the surface ofthe recording body comes into contact with the element selected from theliquid and/or the solid to decreases the receding contact angle of thesurface of the recording body, that is to say, the liquid-attractingtreatment, and the non-image region of the recording body is then heatedselectively by the image forming means in the absence of the contactingelement. The above image forming means comprises the multi-head having aplurality of heating sources for the recording body. The same pixel canbe written simultaneously by the plurality of heating sources

FIG. 17(B) and FIG. 17(C) show views to explain the recording methodaccording to the present invention. FIG. 17(B) illustrates a record viewof a first rotation of the recording body 10 and FIG. 17(C) illustratesa record view of a second rotation of the recording body 10. In thesefigures, a portion having a slating line indicates a pixel writtenalready and a portion having X mark indicates a pixel to be written dueto heating failure. A blank portion indicates a pixel to be writtenlater. For example, in a case where the forth heating source fails towrite, image formation is accomplished by use of odd heating sources(the third and the fifth heating sources) which are usually not used. Asshown in FIG. 17(C), an intended image can be obtained. This results inprevention of generation of unheated, i.e. non-imaged region, so thatgeneration of a line of scumming can be eliminated.

[Example]

-   1. An ink was used as listed in Table 3.-   2. As the recording body, the following was used: Material:    Acrylate-based material containing a fluorine atom.-   Substrate 1: PET film roll.    -   (250 mm×50 mm, 100 μm thickness) for thermal head.-   Substrate 2: Direct matted PET film sheet    -   (220 mm×350 mm, 180 μm thickness) for thermal head.-   Substrate 3: Direct matted PET film roll    -   (350 mm×10 m, 100 μm thickness) for thermal head.-   Substrate 4: Direct matted PET film sheet    -   (350×540 mm, 50 μm thickness)+2 am thickness of carbon layer        (light-absorbing layer) for laser source.-   Substrate 5: Direct matted PET film roll    -   (350 mm×10 m, 100 μm thickness)+3 μm thickness of carbon layer        (light-absorbing layer) for laser source.-   3. As developing means, development was carried out with an ink    roller of a nitrile rubber (hardness is 50).-   4. As a recording paper, use was made of a wood free paper, a    slightly coated paper, a coated paper, an art paper, a synthetic    paper and a plain paper.-   5. As the image forming means, experiments was conducted with the    following means.    -   5-1) 600 dpi thermal head    -   5-2) 300 dpi thermal head

5-3) 70 W semiconductor laser TABLE 3 USED INK NUMBER SPECIES SUB-NUMBERPRODUCT NAME OR COMPOSITION 1 INK FOR {circle over (1)} AQUALESS SUPERKB BLACK CYAN MAGENTA YELLOW M (TOYO INK) WATER-LESS {circle over (2)}AQUALESS FIVE K2 BLACK CYAN MAGENTA YELLOW M (TOYO INK) LITHOGRAPHY{circle over (3)} AQUALESS SUPER FC BLACK CYAN MAGENTA YELLOW YXU (TOYOINK) {circle over (4)} NEW ALPO G BLACK CYAN MAGENTA YELLOW M (TOKA CO.LTD) {circle over (5)} WATERLESS S PL BLACK S (THE INCTEC INC) {circleover (6)} WATERLESS S GT BLACK N (THE INCTEC INC) 2 AQUEOUS INK {circleover (1)} 5 wt % BLACK PIGMENT + 20 wt % POLYETHYLENEGLYCOL + 75 wt %POLYVINYL PYRROLIDONE {circle over (2)} AQUEOUS DYE INK (INCLUSION OF 5wt % POLYVINYL ALCOHOL (PVA))

In a case where the following image forming means was used, in general,even heating sources was used to write the recording body.

-   1. 600 dpi thermal head (Manufactured by Toshiba Co.    Ltd.)/(resistance: 3000 Ω, pulse width: pulse row of 8 μs, applied    voltage: 16 V).-   2. 300 dpi thermal head (Manufactured by Kyosera Co.    Ltd.)/(resistance: 1000 Ω, fundamental pulse width: 0.3 ms, applied    voltage: 12 V).

When the recording body is made the first rotation, the heating sourceis movable in a main scanning direction by one pixel and there cordingbody is then made the second rotation. A spiral writing is carried outto complete image formation. When failure of the even heating sourcestook place, the odd heating sources was activated to write a pixel whichhas not written by the failed heating source, so that image formationcan be carried out even when the heating source fails to write.

In a case where the following image forming means was used, in general,one light source write 1500 pixels per one line.

-   3. 70 W semiconductor laser x 84 of A4 size multi-head (spot shape:    Φ20 μm, arrangement of light source 1500 pixel pitch). When failure    of the light source took place, a light source adjacent to the    failed light source is activated to write, so that image formation    can be carried out even when the light source fails to write.

FIG. 18 illustrates an essential structural view to explain otherembodiment according to the present invention. The image formingapparatus includes the recording body 10, the image region bOA, a marginregion 10B and the multi-head 50. The multi-head 50 has a failed heatingsource 501 which is always in a heated state. In a case where the failedheating source 501 which is always in the heated state is generated andthe failed heating source 501 is disposed in the margin region 10 b,other heating source is not compensated for the failed heating source501, so that time required to compensation for writing is diminished,thereby lowering capacity of the control program.

[Example]

As the ink used, the recording body, the developing means, the recordingpaper and the image forming means, the same was used as the aboveexperiment. With the same image forming means and under conditions ofthe same as the above example, when image formation was accomplished,the heating source of the image forming means located in the marginregion was always in the heated state due to inability of controlthereof. As a result of using the failed heating source in the heatedstate, the margin region was heated without problems.

FIG. 19 illustrates an essential structural view to explain otherembodiment according to the present invention. The image formingapparatus includes the recording body 10, the multi-head 50, a controlpart 60 for moving the head and a counter 61 for counting the number ofprinting. The multi-head 50 is moved in the main scanning direction(shown by an arrow B) by the control part 60 each time a predeterminedamount of printing is counted by: the counter 61. This inhibits thefailed heating source caused by an excess use thereof.

[Example]

As a result of experiments conducted with the same ink, the samerecording body, the same developing means, the same recording paper andthe same image forming means as the above example, the number of theheating source corresponding to the margin region was moved each timeimage formation was carried out for 500 sheets of the recording body ofA3 region. As a result, the number of generation for failure of theheating source was decreased. The experimental results are listed inTable 4. TABLE 4 With respect to a lifetime of thermal head ConventionalThe heating element was broken down Lifetime after operationcorresponding to 1000 sheets/A3. Lifetime according The heating elementwas broken down to the present after operation corresponding to 3000invention sheets/A3. With respect to a lifetime of semiconductor laserConventional The laser source was broken down after Lifetime operationcorresponding to 100000 sheets/A3. Lifetime according The laser sourcewas broken down after to the present operation corresponding to 200000invention sheets/A3.

FIG. 20 illustrates an essential structural view to explain otherembodiment according to the present invention. The image formingapparatus includes the recording body 10, the multi-head 50, the controlpart 60 for moving the head and a timer 62. The multi-head 50 is movedin the main scanning direction (shown by an arrow B) by the control part60 through the timer 62 every predetermined period. This inhibits thefailed heating source caused by an excess use thereof.

[Example]

With use of the same ink, the same recording body, the same developingmeans, the same recording paper and the same image forming means as theabove example, the heating source corresponding to the number of themargin region was moved in the main scanning direction every other month(image formation was carried out for 500 sheets of the recording body ofA3). As a result, the number of generation for failure of the heatingsource was decreased. The experimental results are listed in Table 5.TABLE 5 With respect to a lifetime of thermal head Conventional Theheating element was broken down Lifetime after operation correspondingto 1000 sheets/A3. Lifetime according The heating element was brokendown to the present after operation corresponding to 3000 inventionsheets/A3. With respect to a lifetime of semiconductor laserConventional The laser source was broken down after Lifetime operationcorresponding to 100000 sheets/A3. Lifetime according The laser sourcewas broken down after to the present operation corresponding to 200000invention sheets/A3.

FIG. 21 illustrates an essential structural view to explain otherembodiment according to the present invention. The imaging formingapparatus includes the recording body 10, the multi-head 50, a heater 64for heating the margin region and a control part 63 for moving theheater. In this invention, the heater 64 is compensated for the failedheating source caused by an excess use thereof.

[Example]

By using the same ink, the same recording body, the same developingmeans, the same recording paper and the same image forming means as theabove example, and a ceramic heater as the heater 64 for heating themargin region, image formation was carried out for 1000 sheets of therecording body of A3. As a result, the number of generation for failureof the heating source was decreased and reliability for the heatingsource was improved. The experimental results are listed in Table 6.TABLE 6 With respect to a lifetime of thermal head Conventional Theheating element was broken down Lifetime after operation correspondingto 1000 sheets/A3. Lifetime according The heating element was brokendown to the present after operation corresponding to 10000 inventionsheets/A3. With respect to a lifetime of semiconductor laserConventional The laser source was broken down after Lifetime operationcorresponding to 100000 sheets/A3. Lifetime according The laser sourcewas broken down after to the present operation corresponding to 500000invention sheets/A3.

FIG. 22 illustrates an essential structural view to explain otherembodiment according to the present invention. The image formingapparatus includes the recording body 10, the multi-head 50 and athermal head 65 having a low resolution. The thermal head 65 is used instead of the heater 64 in FIG. 21, so that heating time for the marginalregion can be reduced, thereby allowing a time required for imageformation to be decreased.

[Example]

By using the same ink, the same recording body, the same developingmeans, the same recording paper and the same image forming means as theabove example, and 200 dpi thermal head for heating the margin region asthe thermal head having the low resolution, image formation was carriedout for 1000 sheets of the recording body of A3. As a result, the numberof generation for failure of the heating source was decreased andreliability for the heating source was improved. The experimentalresults are listed in Table 7. TABLE 7 With respect to a lifetime ofthermal head Conventional The heating element was broken down Lifetimeafter operation corresponding to 1000 sheets/A3. Lifetime according Theheating element was broken down to the present after operationcorresponding to 3000 invention sheets/A3. With respect to a lifetime ofsemiconductor laser Conventional The laser source was broken down afterLifetime operation corresponding to 100000 sheets/A3. Lifetime accordingThe laser source was broken down after to the present operationcorresponding to 800000 invention sheets/A3.

FIG. 23 and FIG. 24 illustrate views to explain other embodimentaccording to the present invention. FIG. 23 shows a case where the imageforming means is the thermal (multiple) head. In this figure, 71 _(l) to71 _(n) show the thermal head and 72 _(l), to 72 n show a drive IC whichis resistance for detection of failure of the heating source. FIG. 24shows a case where the image forming means is a laser diode. In thisfigure, 75 shows the laser diode, 76 shows a resistance for detection offailure of the laser diode 75, and 77 shows a generating source for apulse voltage in order to drive the laser diode 75. A resistance valueof each heating source of the multi-head and/or a voltage value acrossthe resistance element connected in series with the heating source arechecked to compare a defined value. In this way, the presence of failureof the heating source can be examined to prevent the generation of thenon-image region due to non-heating, so that generation of a line ofscumming can be eliminated.

[Example]

Use was made of the same ink, the same recording body, the samedeveloping means, the same recording paper and the same image formingmeans as the above example.

1. In a Case of the Thermal Head

An initial resistance value of an element resistance of the heatingsource was about. 3000 Ω. When this value became infinite largely, theheating source became failed. The presence of failure of the heatingsource was detected in this way.

2. In a Case of the Semiconductor Laser

An initial value of voltage across the resistance element connected inseries with the laser diode was 200 mV. When this value made zero, thelaser diode became failed. The presence of failure of the laser diodewas detected in this way.

FIG. 25 and FIG. 26 illustrate essential structural views to explainembodiments according to the present invention. In these figure, Bk, C,M and Y represent black, cyan, magenta and yellow colors, respectively.For each color, the image forming apparatus comprises heads 81(Bk),81(C), 81(M) and 81(Y), the recording bodies 82(Bk), 82(C), 82(M) and82(Y), the developing rollers 83(Bk), 83(C), 83(M) and 83(Y), blades84(Bk), 84(C), 84(M) and 84(Y), intermediate transfer bodies 85(Bk),85(C), 85(M) and 85(Y), and pressing rollers 86(Bk), 86(C), 86(M) and86(Y). In an embodiment of FIG. 26, the image forming apparatus includesa single common pressing roller 87 in stead of the individual pressingrollers 86(Bk), 86(C), 86(M) and 86(Y). The recording paper 91 is fed insequence between the pressing roller and the intermediate transferbodies. The image forming apparatus comprises a plurality of the aboveimage forming means to produce a multi-color image with high quality.

[Example]

By using the same ink, the same recording body, the same developingmeans, the same recording paper and the same image forming means as theabove example, and also four image forming means, a multi-color printingapparatus can be obtained with the long lifetime and high reliability bythe above method in which the failed heating source can be detected.

In the image forming apparatus which is applicable to the presentinvention, negative writing is performed by selectively heating thenon-image region of the recording body 10 so as to form theliquid-repelling state of the non-image region and then leaving theimage region of the recording body 10 state of liquid-attracting to formthe latent image. More specifically, the recording body 10 has thesurface characteristics that the receding contact angle decreases whenthe surface of the image recording body in the heated state is broughtinto contact with the liquid (the liquid-attracting state), and thereceding contact angle increases when the image recording body is heatedin the state where the image recording body is not contact with theliquid (the liquid-repelling state). Image formation can be carried outas follows. After the surface of the recording body is heated in thecontact state with the element selected from the liquid and/or thesolid, or right after the surface is heated and the surface comes intocontact with the element selected from the liquid and/or the solid, thereceding contact angle decreases, that is to say, the liquid-attractingstate. The non-image region of the recording body is selectively heatedby the image forming means in the absence of the contacting element toachieve image formation. As explained above, there may be problems thatimage quality is degraded because of irregularities of heating and heataccumulation of the recording body and/or the image forming means at thetime of negative writing. The present invention provides function ofadjusting the heat amount of the image forming means at the time ofnegative writing. More particularly, the present invention furtherprovides improvement of the irregularities of heating and heataccumulation of the recording body and/or the image forming means at thetime of negative writing in which a writing amount is very large.

FIG. 27 illustrates a schematic view to explain one example in a casewhere the writing heat amount is adjusted by modulating a pulse width.FIG. 27(A) illustrates a flow diagram showing procedures of operationand FIG. 27(B) illustrates a time chart to explain the operation. InFIG. 27(A), 111 shows counting part for counting a heating time (i.e.,counting the number of count of a fundamental clock), 112 shows aproducing part for producing a signal to drive the image forming means(i.e., a counter) and 113 shows the image forming means (for example,the thermal head, laser source or the like). The counting part 111computes the count number N by using a formula (1) with a control signalfor the heating amount (factor K) and the fundamental clock period so asto determine the count number N from the fundamental clock. Theproducing part 112 for producing a signal to drive the image formingmeans includes the counter and N pulse is counted from the abovefundamental clock by the counter. When the number N is below a definedcount value, the number N is made H (high) and when the number N becomesthe defined count value, the number is made L (low). That is to say,When the counter receives a trigger pulse, a gate of the counter is madeH to initiate the counting and the image forming means is driven(heating or light emission) until the counter counts the number N of thefundamental clock pulse.(the fundamental heating time)/(the fundamental clock period)  (1)

FIG. 28 shows a schematic view to explain one example in a case wherethe writing heat amount is adjusted by modulating the pulse number. FIG.28(A) shows an essential structural view to explain the operation andFIG. 28(B) shows a time chart to explain the operation. In FIG. 28(A),115 shows a producing part for producing a signal for the image formingmeans (a producing part for producing a restriction signal of a drivepulse number), 116 shows a AND circuit, 117 shows a producing part forproducing a signal for a drive pulse of the image forming means and 118shows the image forming means. The producing part 115 determines thefundamental clock count number N from the heating amount control signal(K) and the fundamental clock period by using the formula (1) so as togenerate the restriction signal for the drive pulse number of the pulsewidth defined by the count number N. The AND circuit generates a logicsum from the control signal for the drive pulse number produced at theproducing part 115 for producing the restriction signal of the imageforming means drive pulse number and a pulse for drive of the imageforming means produced at the producing part 117 for producing the drivesignal of the image forming means, so as to form the drive pulse (pulsenumber) for the image forming means to drive the image forming means118.

[Example]

-   1. An ink was used as listed in Table 3.-   2. As the recording body, the following was used: Material:    Acrylate-based material containing a fluorine atom (LS317,    manufactured by Asahi Glass Co. Ltd,.).-   Substrate 1: PET film roll.    -   (250 mm×50 mm, 100 μm thickness) for thermal head.-   Substrate 2: Direct matted PET film sheet    -   (220 mm×350 mm, 180 μm thickness) for thermal head.-   Substrate 3: Direct matted PET film roll    -   (350 mm×10 m, 100 μm thickness) for thermal head.-   Substrate 4: Direct matted PET film sheet    -   (350×540 mm, 50 μm thickness)+1 μm thickness of carbon layer        (light-absorbing layer) for laser source.-   Substrate 5: Direct matted PET film roll    -   (350 mm×10 m, 100 μm thickness)+1 μm thickness of carbon layer        (light-absorbing layer) for laser source.-   3. As developing means, development was carried out with an ink    roller of the nitrile rubber (hardness is 50).-   4. As a recording paper, use was made of a wood free paper, a    slightly coated paper, a coated paper, an art paper, a synthetic    paper and a plain paper.

As the image forming means and the method for adjusting the heat amount,experiments was conducted with the following apparatus.

(1) 600 dpi thermal head (manufactured by Toshiba Co.Ltd,.)/(Resistance: 300 Ω pulse width a pulse row of 8 μs, appliedvoltage: 16 V) The head has function that the head is driven by varyingthe pulse number.

(2) 300 dpi thermal head (manufactured by Kyosera Co.Ltd,.)/(Resistance: 1000 Ω, fundamental pulse width: 0.3 ms, appliedvoltage: 12 V) The head has function that the head is driven by varyingthe pulse number.

(3) 200 mW semiconductor laser

(spot shape; φ 20 μm) The head has function that the head is driven byvarying the pulse number.

(4) 50 mW semiconductor laser x 16 of 1270 dpi multi-head (spot shape; Φ20 μm) The head has function that the head is driven by varying thepulse number.

As a result, good writing was performed without the irregularities ofheating as shown in Table 8. TABLE 8 USED INK NUMBER SPECIES SUB-NUMBERPRODUCT NAME OR COMPOSITION 1 INK FOR {circle over (1)} AQUALESS SUPERKB BLACK CYAN MAGENTA YELLOW M (TOYO INK) WATER-LESS {circle over (2)}AQUALESS FIVE K2 BLACK CYAN MAGENTA YELLOW M (TOYO INK) LITHOGRAPHY{circle over (3)} AQUALESS SUPER FC BLACK CYAN MAGENTA YELLOW YXU (TOYOINK) {circle over (4)} NEW ALPO G BLACK CYAN MAGENTA YELLOW M (TOKA CO.LTD) {circle over (5)} WATERLESS S PL BLACK S (THE INCTEC INC) {circleover (6)} WATERLESS S GT BLACK N (THE INCTEC INC) 2 AQUEOUS INK {circleover (1)} 5 wt % BLACK PIGMENT + 20 wt % POLYETHYLENECLYCOL + 75 wt %POLYVINYL PYRROLIDONE {circle over (2)} AQUEOUS DYE INK (INCLUSION OF 5wt % POLYVINYL ALCOHOL (PVA))

FIG. 29 illustrates an essential structural view to explain one exampleto detect the temperature of the recording body 120 comprising the basebody 121 and the recording layer 122. FIG. 29(A) shows a case of usingan infrared radiation thermometer which is a non-contact type and FIG.29(B) shows a case of using a thermistor, a thermocouple and the likewhich are a contact type. In order to detect the temperature a surfaceof the recording body 120, FIG. 29(A) shows one example which uses theinfrared radiation thermometer 124 or the like which are the non-contacttype, while FIG. 29(B) shows the other example which uses thethermometer 125 such as thermistor, the thermocouple or the like whichare the contact type. By using these thermometers, the temperature ofthe surface of the recording body 120 can be detected and output of thelaser source 123 is adjusted on the basis of the detected output, sothat the surface temperature of the recording body can be controlled toa suitable temperature.

[Example]

Under the same condition as the above example (the ink, the recordingbody, the developing means and the recording paper) and by using thesame image forming means and the method for adjusting the heatingamount, detecting means for detecting the temperature are used asfollows:

-   1. Thermistor—the back surface temperature of the recording body.-   2. Thermocouple—the back surface temperature of the recording body.-   3. Infrared radiation thermometer—the surface temperature of the    recording body.    An optimal heating amount was supplied for the heating source, such    as the laser source or the like, on the basis of a base temperature    of the recording body, so that image formation could be carried out    with high quality.

FIG. 30 shows a schematic view to explain one example according to thepresent invention. A serial head is shown in this figure, in which theimage forming means is moved in the main scanning direction to achieverecording. As shown in FIG. 30, each coefficients k, j and i isestablished to the first pixel, the second pixel and the third pixel infront of pixel of interest, respectively. According to the heated pixels(k, j, i, . . . ), a heating time is calculated by multiplying thefundamental heating time by the each set coefficient of respectivepixel, although a relationship of values for each coefficient isk<J<i<1.

In this embodiment, heating amount for writing is adjusted according toheating information of a pixel adjacent to a pixel to be heated(hereinafter referred to as pixel of interest) and a pixel written withthe pixel of interest at the same time or the pixel written already.This results in inhibition of the temperature irregularities of thepixel of interest which is heated based on the temperature condition foradjacent pixel, so that image formation can be performed with highquality.

FIG. 31 shows a schematic view to explain other example according to thepresent invention. This figure illustrates a case of using a line head.All pixels are written simultaneously or at the same time substantiallyby the use of the line head. In a case where the all pixels are writtensimultaneously or approximately at the same time, when all pixels arewritten simultaneously, a relationship is as follows:

-   -   k=1    -   j=m    -   i=n    -   and k<j<I<1. For example, in a case where two pixels represented        by n−1 and n+2 are written, a heating time is calculated by the        following formula (2):        (the fundamental heating time)×k×m (2)

FIG. 32 illustrates a schematic structural view to explain a controlpart of a printing machine to carry out the present invention. Pixelinformation from a personal computer (PC) 128 is accumulated in a linebuffer 132 through an I/F 131 of the control part 130 of the printingmachine. The pixel information is latched in one line buffer 133 everyother line and is send into a producing part 134 for producing an actualwriting image data. For the image data per one line of the producingpart 134 for producing the actual writing image data, a signal componentof heating energy for each pixel is added by a data buffer 135 for anenergy and the image is formed by the image forming means 129.

[Example]

Under the same condition as the above example and by using the sameimage forming means and the same method for adjusting heating amount asthe above example, writing was carried out. As a result, an influence ofthe temperature irregularities produced in the pixel of interest can beinhibited according to the heating state of the adjacent pixel, therebyproducing high quality image.

FIG. 33 shows a schematic view to explain other embodiment according tothe present invention. Since the influence of the temperatureirregularities produced in the pixel of interest according to heatrecords of a plurality of lines written already so that the high qualityimage can be produced, the heating amount for writing can be changedaccording to the heat records of the plurality of lines which arewritten already and are in the same main scanning direction or in a nearscanning direction.

FIG. 33 shows an example of a case where pixels in the main scanningdirection are written at the same time, considering three lines writtenalready. In this case, by using a value which is determined by thefollowing formula (3);g<f<e<c<b<a<1 and b=d, g=h, e=1 (3)and a threshold table, writing energy for some steps can be obtained.

FIG. 34 illustrates a schematic structural view showing a structuralexample of the control part of the printing machine to carry out thepresent invention. The basic operation is the same as the case of FIG.32. In this embodiment, the line buffer 132 has memory for some lines,and the image data for some lines written already produced actually inthe producing part 134 for producing the actual image data is returnedto the line buffer 132 per the line so as to establish the relationshipas shown in FIG. 33. For the pixel of interest, the heating energy iscalculated by the formula (3). From one line buffer 133, the pixelinformation per one pixel is serially transmitted to the producing partfor producing the actual writing image data and the signal component forthe heating energy is added to each pixel of the image data per one lineby the data buffer 135 for the energy, so that the pixel informationthus produced is transmitted to the image forming means 129 per one lineso as to achieve recording.

FIG. 35 shows an essential structural view to explain other embodimentaccording to the present invention. In this figure, 136 shows a drivepixel number counter provided in stead of the line buffer 133 shown inFIG. 32 and the other is the same as shown in FIG. 32. However, thepresent invention inhibits the irregularities of heating amount producedby an amount driving simultaneously, so that the high quality image canbe produced. The heating energy amount from the image forming means(multi-head) having the plurality of heating sources for the recordingbody can be changed by calculating the number of the heating source(pixel) heating simultaneously with the drive pixel number counter 136,according to the amount of the heating source driving simultaneously.For example, by referring to the coefficient table corresponding to thedrive pixel number, multiply with fundamental heating time determinesthe heating time.

FIG. 36 shows an essential schematic view to explain one embodimentaccording to the present invention. FIG. 36(A) shows a case of theserial writing head in which 2 shows the recording body roller, 10 (or30, or 120) shows the recording body, 141 shows a recording head. Aswell-known, the recording body roller 2 is rotated in a sub-scanningdirection as shown by an arrow A and the recording head 141 executes ato-and-fro motion in the main scanning direction as shown by an arrow B.According to the present invention, however, in order to produce thehigh quality image with elimination of heat accumulation at the time ofwriting and inhibition of heating irregularities, writing is carried outmore than every at least other line in the main scanning direction (theB direction) (portions having a slanting line is a pixel to be writtenin FIG. 36). For example, as shown in FIG. 36(B), writing is carried outon every other pixel in the first rotation (a blank portion is a pixelto be written later) and as shown in FIG. 36(C), residual pixels (whichare pixels shown in FIG. 36(B)) are written in the second rotation.

FIG. 37 shows an essential schematic view to explain other embodimentaccording to the present invention. 142 shows the line head in FIG.37(A) illustrating an example of a line writing head. However, as shownin FIG. 37(B), writing is carried out every other line in the firstrotation in the sub-scanning direction (A direction), that is to say,the portion having the slanting line is recorded. As shown in FIG.37(C), a blank portion which is not written in the first rotation(corresponding to the blank portion of FIG. 37(B)) is written in thesecond rotation.

FIG. 38 shows an essential schematic view to explain one embodimentaccording to the present invention. In this figure, 151 shows a drivepixel number counter for one line, 152 shows a determining part fordetermining the writing time for one line, 153 shows a counter, 154shows a producing part for producing a fundamental clock to dive thecounter 153 and 155 shows a motor driver for driving the recording bodyroller.

Additionally, FIG. 39 illustrates a schematic view showing arelationship between a motor driven by the motor driver 155 as shown inFIG. 38 and the recording body drum driven by the motor. In this figure,155 shows the motor driver for driving the recording body roller asstated above, 156 shows a motor for driving the recording body rollerdriven by the motor driver 155, 157 shows a gear for transmitting arotation of the motor 156 to the recording body drum, 2 shows therecording body roller, 10 shows the recording body and 142 shows theline head.

According to the present invention, however, by changing a writing rateaccording to image information, irregularities of accumulation ofheating amount at the different time of writing in response to imageinformation is inhibited so as to produce the high quality image. Asshown in FIG. 38, the writing time for one line is determined bycounting the number of drive pixels within one line. Determination ofthis writing time, for example, is made by referring to a line perioddata corresponding to the count value (this line period data is thecount number of the fundamental clock pulse) of a table. The countnumber thus determined is counted by counting the fundamental clockpulse by the counter 153, so that the motor 156 for driving therecording body roller is driven during the period of this count (theperiod is the period between the count commencement and the count end).In a case of many drive pixel numbers, this results in a decrease in thewriting rate by increasing the time required to write the next linebecause of an increase in accumulation of heating amount of therecording body head.

FIG. 40 illustrates an essential structural view to explain otherembodiment according to the present invention. In this figure, 161 showsa detecting part for detecting the temperature of the recording body,162 shows a determining part for determining the writing time for oneline (determination is based on reference of the line period datadetermined according to the temperature of the recording body to thetable), 163 shows a counter for counting the count number (or the time)determined by the determining part 162 for determining the writing timefor one line and 164 shows a producing part 164 for producing thefundamental clock. By counting the fundamental clock pulse, establishedcount value or the time at the counter 163 is counted at the counter 163so as to drive the motor driver 165 for driving the recording bodyroller during the time.

FIG. 41 illustrates a schematic view showing a relationship between themotor driven by the motor driver 165 for driving the recording bodyroller and the recording body roller driven by the motor. In thisfigure, 165 shows the above motor driver for driving the recording bodyroller, 166 shows the motor for driving the recording body roller drivenby the motor driver 165, 167 shows the gear for transmitting therotation of the motor 166 to the recording roller 2, 2 shows therecording body roller, 10 shows the recording body, 142 shows the linehead and 168 shows the thermometer for detecting the temperature of therecording body, for example the infrared radiation thermometer.

According to the present invention, however, an increase in thetemperature of the recording body at the time of writing can be reducedby changing the writing rate according to the increase in thetemperature of the recording body, so that image formation is carriedout with high quality. As stated above, the increase in the temperatureof the recording body 10 can be inhibited by retarding a rotation rateof the motor 166 for driving the recording body roller in a case of hightemperature of the recording body 10.

FIG. 42 illustrates an essential diagrammatic view to explain otherembodiment according to the present invention. In this figure, 171 showsa counter for counting the number n of a writing line at the beginningof writing. 172 shows a set counter for setting the number N of thewriting line. 173 shows a comparator. 174 shows a writing energy flagsetting part. In the comparator 173, by comparing the number n of thewriting line at the beginning of writing from the counter 171 with a setnumber N of the writing line from the set counter 172,

-   -   writing energy is increased during n<N and    -   writing energy is decreased during n>N.        Because of this, image formation is carried out with increased        heating amount at the beginning of writing so that shortage of        the heating amount can be prevented until the temperature of the        recording body is stabilized, so as to produce the high quality        image. In practice, 200 lines in the marginal region are heated        at the beginning of writing with energy having 1.2 times the        usual energy, thereby leading to the good result.

FIG. 43 shows a diagrammatic view to explain operation of the presentinvention. In this figure, 2 shows the recording body roller, 10 showsthe recording body, 143 and 144 show multi-head. In FIG. 43(A) themulti-head of the laser source 143 is used, while in FIG. 43(B) the linethermal head 144 is used.

However, in this invention the image forming means has the multi-headand by carrying out writing more than every at least other pixel in thesame line, accumulation of heat at the time of writing can be inhibitedso as to inhibit the uneven heating, thereby producing the high qualityimage. In a case where laser source multi-head 143 is used in FIG.43(A),

(a1) every other pixel, four pixels, i.e., the first pixel, the third,the fifth and the seventh pixels are written at the same time, and then

(a2) four pixels, i.e., the second, the fourth, the sixth and the eighthpixels are written at the same time,

(a3) with a shift of eight pixels in the main scanning direction thesimilar writing is carried out sequentially to achieve writing for oneline. The next line is similarly written with the shift of eight pixelsin an opposite direction of the main scanning direction from the sameposition, or after moving to a home position of the main scanningdirection, the same writing as the previous line is carried out so as toachieve writing of the whole image region.

Additionally, in a case where the line thermal head 144 is used,

(b1) For each heating element block (4 blocks in all), i.e., for 1pixel, image formation for one line is accomplished by writing 8 timesin all with an even pixel and an odd pixel driven alternatively. Thenext line is similarly written so as to achieve writing of the wholeimage region.

(b2) With the recording body 10 moving in the sub-scanning direction,after a half pixel of each line is written by driving every other pixelfor each heating element block (4 blocks in all), i.e., the even pixelor the odd pixel to achieve writing from an initial line to a finalline, next one rotation writing is carried out by driving the odd pixelor the even pixel which is not driven, so that writing of the wholeimage region can be accomplished.

FIG. 44 shows a diagrammatic view to explain other embodiment accordingto the present invention. The multi-head 145 using the laser source asthe heating source is shown in FIG. 44(A), while the multi-head 146using the heating element as the heating source is shown in FIG. 44(B).However, the present invention provides the image forming apparatuscomprising the multi-head having the heating source formed more thanevery other pixel, so that accumulation of heat can be inhibited at thetime of writing and heating irregularities can be inhibited, therebyproducing the high quality image.

In a case where use is made of 50 mW semiconductor laser x 4 multi-head(spot shape: Φ21 μm) as the laser source multi-head 145 shown in FIG.44(A), 4 pixels are simultaneously written every 2100 pixels (a1), afterone rotation is performed for the recording body, writing for 2100rotation is carried out while shifting the light source one pixel, sothat writing of the whole image region is accomplished (a2).

In a case of the thermal head as shown in FIG. 44(B), 300 dpi thermalhead is used, in which resistance is 1000 Ω, a fundamental pulse widthis 0.3 ms, applied voltage is 12V and shape of heating element is 40×20μm (the main scanning direction x sub-scanning direction). For eachheating element (4 blocks in all), the only even or the only odd pixelsis driven every other pixel (b1), and after the first rotation iscarried out for the recording body, the head is shifted one pixel in themain scanning direction and writing for second rotation is carried outso that writing of the whole image region is accomplished.

FIG. 45 illustrates an essential structural view to explain otherembodiment according to the present invention. In this figure, 2 showsthe recording body roller, 10 shows the recording body, 147 shows themulti-head. The image forming means according to the present inventioncomprises the multi-head 147 and writing is carried out in the same linemore than every at least other pixel. Spiral writing is carried out bywriting while shifting the head in the main scanning direction little bylittle, so that accumulation of heat is inhibited at the time of writingand heating irregularities can be inhibited, thereby producing the highquality image.

In FIG. 45, in the case where the laser source multi-head 143 as shownin FIG. 43 is used as the multi-head 147, 4 pixels are simultaneouslywritten every other pixel. One rotation is performed for the recordingbody 10 and 2100 rotations is also performed while shifting the lightsource in the main scanning direction little by little to move adistance corresponding to one pixel so as to form the whole image byspiral writing. In the case where the thermal head 144 as shown in FIG.43 is used as the multi-head, for each heating element block (4-blocksin all), the only even or the only odd pixels are driven every otherpixel. After the first rotation is performed for the recording body, thesecond rotation is also performed while shifting the head in the mainscanning direction little by little to move the distance correspondingto one pixel so as to accomplish the whole image formation by spiralwriting. FIG. 45(A) shows a state where a half rotation is carried outfor the recording body roller 2 and the head is shifted to a right sidethe distance of half pixel. FIG. 45(B) shows the state where secondrotation is carried out for the recording body roller 2 and the head isshifted to the right side the distance of two pixels.

FIG. 46 shows a diagrammatic view to explain other embodiment accordingto the present invention. In this figure, 2 shows the recording bodyroller, 10 shows the recording body and the image forming meanscomprises the multi-head and writes at least more than one pixel in thesame line (FIG. 46(A)). After the final line is written, the imageforming means or the recording body is movable in the main scanningdirection so as to continue writing, so that accumulation of heat can beinhibited at the time of writing and heating irregularities can beinhibited, thereby producing the high quality image. In FIG. 46(A), theportion having the slanting line is the pixel to be written(irrespective of heating), while the portion having blank space is thepixel to be written lately. In the case where the laser sourcemulti-head is used, for example, 4 pixels are simultaneously writtenevery 2100 pixels, the whole image formation is accomplished by writingfor 2100 rotations while shifting the light source one pixel each timeone rotation is carried out for the recording body. Additionally, in thecase where the thermal head is used, for example, for each heatingelement block (4 blocks in all), the only even or the only odd pixels isdriven every other pixel and after one rotation is carried out for therecording body, the whole image formation is accomplished by writing thesecond rotation while shifting the head one pixel in the main scanningdirection.

In a case of constructing a multi-color image forming apparatus by theuse of the present invention, a plurality of the above-mentioned imageforming means is provided to form the construction as shown in FIGS. 25and 26. It should be noted that in FIGS. 25 and 26 Bk represents black,C represents cyan, M represents magenta and Y represents yellow. Foreach color, the multi-color image forming apparatus comprises the head81, the recording body 82, the developing unit 83, the blade 84, theintermediate transfer roller 85 and the pressing rollers 86 and 87. Inthe example of FIG. 25, the pressing rollers 86 are provided for eachcolor, while in the example of FIG. 26 the pressing roller 87 is thecommon roller for each color. It should be noted that the recordingpaper is designated 91.

As shown in FIGS. 25 and 26, however, in the case where the multi-colorhigh quality image is formed by providing the plurality of image formingmeans, image formation is carried out for black, cyan, magenta andyellow recording bodies with four multi-head 143 as shown FIG. 43(A),when the laser source multi-head is employed. When the thermal head isemployed, image formation is carried out for black, cyan, magenta andyellow recording bodies by the image forming method which employs fourmulti-head 144 as shown in FIG. 43(B), for example, 300 dpi multi-head

As mentioned above, according to the present invention, the recordingbody 10 (or 30) is heated, for example, the recording body 10 is heatedby the laser light to form the latent image. This heating can alsorealized by scanning the laser light on the recording body by means ofthe rotating multi-face mirror. A plane light scanning apparatus inwhich the laser light which is modulated in response to imageinformation signal is scanned by means of the rotating multi-face mirrorso as to form the latent image is widely used in a laser beam printerbased on an electrophotographic method. The light is scanned on aprecharged photoreceptor in response to image information to form anelectrostatic latent image by photoelectric conversion. Because thephotoreceptor has a high sensitivity, a few to several tens copieshaving a A4 size can be printed per one minute by means of a few mWlaser.

However, in a case where the light is scanned on the recording bodyhaving the light-heat converting layer or the recording body comprisingthe recording layer having the light-heat converting agent dispersedtherein to form the latent image on the above recording body bylight-to-heat conversion, since the recording body has an extremely lowsensitivity, a high power laser may be used, or an increased scanningtime may be required to realize writing.

However, in order to reduce the apparatus cost, writing can be realizednot by using an expensive high power laser but by increasing thescanning time. The increased scanning time results in slow scanningrate, for example, in a type in which rotating multi-face mirror ismoved to rotate by the motor, the rotating multi-face mirror results indrive at low revolution. However, in this case, because the inertiaaction due to the rotation does not act on, the rotation rate becomesunstable, thereby giving rise to problems regarding rotationirregularities of the multi-face mirror, and changes in scanning rate ofthe laser beam and in scanning time. This results in irregularities oflight-heat conversion. This also results in irregularities of imagedensity, dot and the line size (such as broadening and narrowing or thelike).

As stated above, in the light scanning apparatus which employs therotating multi-face mirror, in a case where the rotating multi-facemirror is driven at a low revolution by the motor, since the inertiaaction due to the rotation does not act on, the rotation rate becomesunstable, thereby giving rise to problems regarding rotationirregularities of the multi-face mirror, and changes in scanning rate ofthe laser beam and in scanning time. This results in irregularities oflight-heat conversion. This also results in irregularities of imagedensity, dot and the line size (such as broadening and narrowing or thelike). Additionally, because the number of the constituting member islarge and the member is complicated to become expensive, problems to besolved was to reduce the number of the constituting member and tosimplify the member.

FIG. 47 illustrates an essential structural view to explain oneembodiment of the light scanning apparatus according to the presentinvention. In this figure, 151 shows, for example, the semiconductorlaser light source, 152 shows the rotating multi-face mirror (a polygonmirror) and 153 shows a motor for rotating the rotating multi-facemirror 152. The laser light from the laser light source 151 is reflectedat the rotating multi-face mirror 152 to scan the light on the recordingbody 10. The present invention is applicable to a case where the latentimage is formed on the recording body having the light-heat convertingagent by such light scanning method and the scanning rate of lightwriting can stably be realized even when the rate of light scanning islow.

In the light scanning apparatus which employs the rotating multi-facemirror, in a case where the rotating multi-face mirror is driven at thelow revolution by the motor, since the inertia action due to therotation does not act on, the rotation rate becomes unstable, therebygiving rise to problems regarding rotation irregularities of themulti-face mirror, and changes in scanning rate of the laser beam and inscanning time. This results in irregularities of light-heat conversion.This also results in irregularities of image density, dot and the linesize (such as broadening and narrowing or the like).

According to the present invention, in order to solve such problems, themotor is rotated at the high revolution of a stable revolution regionand the rotating multi-face mirror can stably be rotated at the lowrevolution by means of deceleration mechanism 14. As decelerationmechanism 14, use was made of a gear, magnetic pulley idler, pulley beltor the like. This results in stability of the revolution of themulti-face mirror at the low rate, so that the scanning rate andscanning time of the laser beam can be kept constant. This also resultsin reduction of irregularities of image density, dot and the line size(broadening and narrowing) to obtain a low cost light scanning.

Additionally, in order to stabilize the rotation of the motor, becausethe number of the constituting member is large and the member iscomplicated so as to become expensive, it is important to reduce thenumber of the constituting member and to simplify the member. In orderto solve this problem, an inertia mass body 155 is provided on an axisof the motor 153 or the rotating multi-face mirror 152. This inertiamass body 155 preferably has a radius substantially equal to or morethan that of revolution of the rotating multi-face mirror.Alternatively, it is possible to use a discal member having a masssubstantially equal to or more than that of the rotating multi-facemirror. It should be noted that as the discal member use is made of aplate or a casting formed of a metal, such as iron, aluminum, copper,lead or the like. This results in stability of revolution of therotating multi-face mirror at the low rate, so that the light scanningapparatus can be obtained without irregularities of image density, dotand the line size (broadening and narrowing) or the like. Additionally,because the constituting member is only discal member, low costapparatus can be realized.

1. An image forming apparatus comprising an image forming partconfigured to form an image on an image region by selectively heating anon-image region of a recording body, wherein said image forming partcomprises a plurality of image radiation sources for heating saidrecording body and said plurality of image radiation sources are capableof writing the same pixel, and when a failed image radiation sourceoccurs and said failed image radiation source is located at a marginalregion, a region to be written by said failed image radiation source isnot compensated by other image radiation source.
 2. The image formingapparatus as claimed in claim 1, wherein said image forming partcomprises a multi-head having a broader recording width than that of animage formation region and a part configured to move said multi-head ina main scanning direction each time a predetermined printing is carriedout.
 3. The image forming apparatus as claimed in claim 1, wherein saidimage forming part comprises a multi-head having a broader recordingwidth than that of an image formation region and a part configured tomove said multi-head in a main scanning direction every predeterminedperiod.
 4. The image forming apparatus as claimed in claim 1, whereinsaid image forming part comprises a heating part configured to heat animage region and a heating part configured to heat a marginal region. 5.The image forming apparatus as claimed in claim 1, wherein said heatingpart configured to heat said marginal region comprises a multi-headhaving a lower resolution than that of said heating part configured toheat said image region.
 6. The image forming apparatus as claimed inclaim 1, wherein detection is carried out for a resistance value of eachimage radiation source of said multi-head and/or a voltage across aresistive element connected in series with said image radiation sourceso as to examine whether or not a failed image radiation source ispresent by comparing, a detected voltage with a defined voltage.
 7. Theimage forming apparatus as claimed in claim 1, wherein said imageforming part comprises a plurality of image forming parts correspondingto each color of respective recording colors.
 8. An image forming methodcomprising the image forming step of forming an image on an image regionby selectively heating a non-image region of a recording body, whereinin said image forming step, a plurality of image radiation sources forheating said recording body are applied and said plurality of imageradiation sources are capable of writing the same pixel, and when afailed image radiation source occurs and said failed image radiationsource is located at a marginal region, a region to be written by saidfailed image radiation source is not compensated by other imageradiation source.
 9. The image forming method as claimed in claim 8,wherein, in said image forming step, a multi-head having a broaderrecording width than that of an image formation region and a partconfigured to move said multi-head in a main scanning direction eachtime a predetermined printing is carried out are applied.
 10. The imageforming method as claimed in claim 8, wherein, in said image formingstep, a multi-head having a broader recording width than that of animage formation region and a part configured to move said multi-head ina main scanning direction every predetermined period are applied. 11.The image forming method as claimed in claim 8, wherein, in said imageforming step, a heating part configured to heat an image region and aheating part configured to heat a marginal region are applied.
 12. Theimage forming method as claimed in claim 8, wherein said heating partconfigured to heat said marginal region comprises a multi-head having alower resolution than that of said heating part configured to heat saidimage region.
 13. The image forming method as claimed in claim 8,wherein detection is carried out for a resistance value of each imageradiation source of said multi-head and/or a voltage across a resistiveelement connected in series with said image radiation source so as toexamine whether or not a failed image radiation source is present bycomparing, a detected voltage with a defined voltage.
 14. The imageforming method as claimed in claim 8, wherein said image forming stepcomprises a plurality of image forming steps corresponding to each colorof respective recording colors.